Registration tools, systems, and methods

ABSTRACT

A registration system including a bone pin guide and a bone pin clamp. The bone pin guide may include a guide body, a first guide including a first guide through-hole having a first longitudinal axis, and a second guide including a second guide through-hole having a second longitudinal axis. The bone pin guide may guide first and second bone pins into a bone via the first and second guides. The bone pin clamp may include a clamp body, first, second, and third clamp through-holes extending through the clamp body, a plurality of registration indents defined on the clamp body, and a clamping mechanism including at least one adjustable fastener. The bone pin clamp may receive the first and second bone pins in the first and third clamp through-holes and guide a third bone pin into the bone via the second clamp through-hole.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S. application Ser. No. 17/189,971, filed Mar. 2, 2021, which application is a continuation of U.S. application Ser. No. 16/970,493, filed Aug. 17, 2020, now U.S. Pat. No. 10,959,857, which application is a national stage application of PCT/US2019/019633, filed Feb. 26, 2019, which claims the benefit of and priority to U.S. Provisional Patent Application No. 62/636,045, filed Feb. 27, 2018. All the afore-mentioned applications are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates generally to surgical systems for orthopedic joint replacement surgery and, more particularly, to methods of intra-operative pelvic registration.

BACKGROUND

Robotic systems are often used in applications that require a high degree of accuracy and/or precision, such as surgical procedures or other complex tasks. Such systems may include various types of robots, such as autonomous, teleoperated, and interactive.

Interactive robotic systems may be preferred for some types of surgery, such as joint replacement surgery, because they enable a surgeon to maintain direct, hands-on control of the surgical procedure while still achieving a high degree of accuracy and/or precision. For example, in knee replacement surgery, a surgeon can use an interactive, haptically guided robotic arm in a passive manner to sculpt bone to receive a joint implant, such as a knee implant. To sculpt bone, the surgeon manually grasps and manipulates the robotic arm to move a cutting tool (e.g., a rotating burr) that is coupled to the robotic arm to cut a pocket in the bone. As long as the surgeon maintains a tip of the burr within a predefined virtual cutting boundary or haptic boundary defined, for example, by a haptic object, the robotic arm moves freely with low friction and low inertia such that the surgeon perceives the robotic arm as essentially weightless and can move the robotic arm as desired. If the surgeon attempts to move the tip of the burr to cut outside the virtual cutting boundary, however, the robotic arm provides haptic feedback (e.g., forced resistance) that prevents or inhibits the surgeon from moving the tip of the burr beyond the virtual cutting boundary. In this manner, the robotic arm enables highly accurate, repeatable bone cuts. When the surgeon manually implants a knee implant (e.g., a patellofemoral component) on a corresponding bone cut the implant will generally be accurately aligned due to the configuration of and interface between the cut bone and the knee implant.

The above-described interactive robotic system may also be used in hip replacement surgery, which may require the use of multiple surgical tools having different functions (e.g., reaming, impacting), different configurations (e.g., straight, offset), and different weights. A system designed to accommodate a variety of tools is described in U.S. patent application Ser. No. 12/894,071, filed Sep. 29, 2010, entitled “SURGICAL SYSTEM FOR POSITIONING PROSTHETIC COMPONENT AND/OR FOR CONSTRAINING MOVEMENT OF SURGICAL TOOL”, which is hereby incorporated by reference in its entirety.

During a hip replacement surgery, as well as other robotically assisted or fully autonomous surgical procedures, the patient bone is intra-operatively registered with a corresponding virtual or computer bone model to correlate the pose (i.e., position and rotational orientation) of the actual, physical bone with the virtual bone model. The patient bone (physical space) is also tracked relative to the surgical robot, haptic device, or surgical tool with at least one degree of freedom (e.g., rotating burr). In this way, the virtual cutting or haptic boundaries controlled and defined on the virtual bone model via a computer can be applied to the patient bone (physical space) such that the haptic device is constrained in its physical movement (e.g., burring) when working on the patient bone (physical space).

Intra-operative registration of the pelvis can be challenging because of the complex geometry of the pelvis and, in particular, the concave nature of the acetabulum. While certain methods exist in the art for registration of a patient pelvis, there is need in the art for registration methods that increase accuracy while decreasing registration time.

BRIEF SUMMARY

Aspects of the present disclosure may involve a system for registering patient data gathered intra-operatively of a first bone with a computer model of the first bone in a coordinate system. The first bone may include a concave portion and forming a joint with a second bone may include a convex portion. The system may include a) a surgical navigation system may include a tracking device and at least one tool configured to be tracked in its movement by the tracking device. The system may further include b) at least one computing device in communication with the surgical navigation system, the at least one computing device storing the computer model of the first bone in the coordinate system. The at least one computing device may perform the following steps: i) receiving first data points of the patient data from first intra-operatively collected points on an articular surface of the concave portion, the first data points collected using the at least one tool, the first data points corresponding in location to a first articular region on the computer model; ii) receiving a second data point from a second intra-operatively collected point on the first bone, the second data point collected using the at least one tool, the second data point corresponding in location to a second virtual data point on the computer model; iii) determining an intra-operative center of rotation from the first data points, the intra-operative center of rotation corresponding to a physical center of rotation of the second bone relative to the first bone; iv) aligning the intra-operative center of rotation with a virtual center of rotation of the computer model in the coordinate system; v) comparing a first distance between the virtual center of rotation and the second virtual data point and a second distance between the intra-operative center of rotation and the second data point; and vi) running a transformation with the patient data and the computer model so as to have them correspond with respect to position and orientation.

Aspects of the present disclosure may involve one or more tangible computer-readable storage media storing computer-executable instructions for performing a computer process on a computing system. The computer process may include a) receiving a plurality of first data points of patient data points captured on a first patient bone in a first location using a tracking device of a navigation system, the first patient bone may include a concave portion forming a joint with a convex portion of a second patient bone, the plurality of first data points representing a first virtual surface profile of the first patient bone at the first location. The computer process may further include b) receiving a second data point of patient data points captured on the first patient bone in a second location using the tracking device, the second location being different than the first location. The computer process may further include c) determining a first center of rotation from the plurality of first data points, the first center of rotation being representative of a physical center of rotation of the second patient bone relative to the first patient bone. The computer process may further include d) locationally matching the first center of rotation with a virtual center of rotation of a computer model of the first patient bone, wherein the plurality of first data points, the second data point, the first center of in the coordinate system, the computer model, and the virtual center of rotation being in a common coordinate system. The computer process may further include e) locationally matching the second data point and a second virtual data point of the computer model to register the patient data points with the computer model with respect to position and orientation, the second virtual data point located on the computer model in a location corresponding to the second location on the first patient bone.

Aspects of the present disclosure may involve a computerized method of intra-operatively registering patient data associated with a first bone with a computer model of the first bone in a coordinate system. The first bone may include a concave portion and forming a joint with a second bone may include a convex portion. The computerized method may include a) receiving first data points of the patient data from first intra-operatively collected points on an articular surface of the concave portion of the first bone, the first data points collected with a tracking device of a navigation system. The computerized method may further include b) receiving a second data point of the patient data from a second intra-operatively collected point on the first bone, the second data point collected with the tracking device, the second data point corresponding in location to a second virtual data point on the computer model. The computerized method may further include c) determining an intra-operative center of rotation of the second bone relative to the first bone from the first data points. The computerized method may further include d) locationally matching the intra-operative center of rotation with a virtual center of rotation of the computer model in the coordinate system. The computerized method may further include e) comparing a first distance between the virtual center of rotation and the second virtual data point and a second distance between the intra-operative center of rotation and the second data point.

In certain instances, the computerized method may further include: f) receiving a third data point of the patient data from a third intra-operatively collected point on the first bone, the third data point collected with the tracking device, the third data point being in a different location on the first bone than the second data point and corresponding in location to a third virtual data point on the computer model; and g) comparing a third distance between the virtual center of rotation and the third virtual data point and a fourth distance between the intra-operative center of rotation and the third data point.

Aspects of the present disclosure may involve a computerized method of registering first patient data associated with a first patient bone and a computer model of the first patient bone in a coordinate system with respect to translation and rotation. The first patient bone may include a concave portion forming a joint with a convex portion of a second patient bone. The computerized method may include a) locking the translation between the first patient data and the computer model of the first patient bone by: i) receiving a plurality of first data points of the first patient data, the plurality of first data points corresponding to first points collected on the first patient bone in a first location, the first points collected with a tracking device of a navigation system; ii) determining an intra-operative center of rotation of the convex portion of the second patient bone relative to the concave portion of the first patient bone from the plurality of first data points; and iii) aligning the intra-operative center of rotation with a virtual center of rotation of the computer model of the first patient bone in the coordinate system.

In certain instances, the computerized method may further include: b) locking the rotation between the first data points and the computer model of the first patient bone by: i) capturing a second data point of the first data points on the first patient bone using the tracking device, the second data point being in a different location than the plurality of first data points and corresponding in location to a second virtual data point on the computer model; and ii) using information associated with the second data point and the second virtual data point to lock the rotation of the first data points with the computer model.

Aspects of the present disclosure may involve a system for guided landmark capture during a registration procedure involving registering intra-operative data associated with a first bone of a patient with a computer model of the first bone. The system may include a) a surgical navigation system may include a tracking device and at least one tool configured to be tracked in its movement by the tracking device. The system may further include b) a display device. The system may further include c) at least one computing device in electrical communication with the display device and the surgical navigation system, the at least one computing device may include: an input; an output; a memory; and a central processing unit (“CPU”) in electrical communication with the input, the output and the memory, the memory may include software for operating a graphical user interface (“GUI”), the at least one computing device configured to: i) display the GUI, and the computer model of the first bone on the display device, the GUI may include a virtual point displayed on the computer model of the first bone, the virtual point corresponding to a physical point on the first bone for intra-operatively capturing with the at least one tool, the GUI may further include a graphic at least partially surrounding the virtual point, the graphic being spaced apart from the virtual point by a radius. The GUI may further be configured to ii) adjust a size of the radius of the graphic based on a change in distance between the at least one tool and the physical point on the first bone.

Aspects of the present disclosure may involve a registration system that includes a bone pin guide and a bone pin clamp. The bone pin guide may include a guide body, a first guide may include a first guide through-hole having a first longitudinal axis, and a second guide may include a second guide through-hole having a second longitudinal axis. The first and second guide through-holes being spaced apart a distance, the first and second longitudinal axes being parallel to each other, and the bone pin guide may guide first and second bone pins into a bone via the first and second guides. The bone pin clamp may include a clamp body, first, second, and third clamp through-holes extending through the clamp body, a plurality of registration indents defined on the clamp body, and a clamping mechanism that may include at least one adjustable fastener. The first and third clamp through-holes being spaced apart the distance, the second clamp through-hole positioned between the first and third clamp through-holes, and the bone pin clamp may receive the first and second bone pins in the first and third clamp through-holes and guide a third bone pin into the bone via the second clamp through-hole.

In certain instances, the bone pin clamp further may include a sleeve coupled to the clamp body and extending distally therefrom, the second clamp through-hole extending through the sleeve.

In certain instances, the plurality of registration indents may include three registration indents positioned on a proximal surface of the clamp body.

In certain instances, the clamping mechanism may include a center lock body and a main lock body positioned within an inner volume of the clamp body.

In certain instances, the main lock body may be biased in position within the inner volume via a plurality of springs.

In certain instances, the clamp body further may include first, second, and third threaded through-holes extending into the clamp body and extending into the first, second, and third clamp through-holes, respectively, and wherein the at least one adjustable fastener may include first, second, and third threaded fasteners may be received within the first, second, and third threaded-through-holes, respectively, so as to extend into the first, second, and third threaded through-holes, respectively.

In certain instances, the registration system further may include a tracker array and a tracker coupling may couple to the tracker array and the bone pin clamp.

In certain instances, the first guide may include a first barrel extending distally from the guide body, the first guide through-hole defined within the first barrel, the second guide may include a second barrel extending distally from the guide body, the second guide through-hole defined within the second barrel.

In certain instances, opposite sides of the guide body each include planar tool engaging surfaces.

Aspects of the present disclosure may involve a registration system that may include at least one bone pin, a clamp, and a sleeve. The at least one bone pin may include a first pin having a pin longitudinal axis. The clamp may include at least one through-bore extending there through, the clamp may receive the at least one bone pin though the at least one through-bore. The sleeve may include a body having a sleeve longitudinal axis, a distal bore extending partially through a distal end of the body, and a proximal bore extending partially through a proximal end of the body. The distal bore may receive a portion of a proximal end of the first bone pin, the proximal bore may receive a distal end of a tracking device that may be tracked in its movement. The tracking device may include a device longitudinal axis, wherein, when the distal bore of the sleeve receives the portion of the proximal end of the first bone pin and when the proximal bore of the sleeve receives the distal end of the tracking device, the sleeve longitudinal axis, the pin longitudinal axis, and the device longitudinal axis are coaxial with each other.

Aspects of the present disclosure may involve a method of surgical registration that may include positioning a bone pin guide adjacent a patient bone. The bone pin guide may include a guide body, a first guide may include a first guide through-hole having a first longitudinal axis, and a second guide may include a second guide through-hole having a second longitudinal axis. The first and second guide through-holes being spaced apart a distance, and the first and second longitudinal axes being parallel to each other. The method may also include delivering a first bone pin into the bone via guidance by the first guide of the bone pin guide. The method may also include delivering a second bone pin into the bone via guidance by the second guide of the bone pin guide. The method may also include removing the bone pin guide from the first and second bone pins. The method may also include positioning a bone pin clamp adjacent the bone such that the first bone pin may be received within a first clamp through-hole of the bone pin clamp, and such that the second bone pin may be received within a third clamp through-hole of the bone pin clamp. The bone pin clamp may include a clamp body, the first clamp through-hole, a second clamp through-hole, and the third clamp through-hole, a plurality of registration indents defined on the clamp body, and a clamping mechanism that may include at least one adjustable fastener. The first and third clamp through-holes being spaced apart the distance, and the second clamp through-hole positioned between the first and third clamp through-holes. The method may also include delivering a third bone pin into the bone via guidance by the second through-hole of the bone pin clamp. The method may also include securing a position of the first, second, and third bone pins relative to the bone pin clamp via actuation of the clamping mechanism. The method may also include attaching a tracker array to the bone pin clamp. And the method may also include contacting at least one of the plurality of registration indents with a navigated instrument in a registration procedure.

In certain instances, the bone pin clamp further may include a sleeve coupled to the clamp body and extending distally therefrom, the second clamp through-hole extending through the sleeve.

In certain instances, the clamping mechanism may include a center lock body and a main lock body positioned within an inner volume of the clamp body.

In certain instances, the main lock body may be biased in position within the inner volume via a plurality of springs.

In certain instances, the clamp body further may include first, second, and third threaded through-holes extending into the clamp body and extending into the first, second, and third clamp through-holes, respectively, and wherein the at least one adjustable fastener may include first, second, and third threaded fasteners may be received within the first, second, and third threaded-through-holes, respectively, so as to extend into the first, second, and third threaded through-holes, respectively.

Aspects of the present disclosure may involve a computer-implemented method of registration that may include receiving first data points in a point-cloud corresponding to points on a patient bone in a first location that are registered with a navigated instrument. The method may also include receiving second data points in the point-cloud corresponding to points on a bone pin clamp that may be secured to the patient bone in a second location via a plurality of bone pins, the bone pin clamp may include a plurality of registration indent defining a plane, the plane being a known distance from the patient bone. The method may also include determining a bone surface point at the second location from the defined plane and known distance. And the method may also include registering the first and second data points in the point cloud with image data of the patient bone.

In certain instances, the bone surface point may be a point where one of the plurality of bone pins extends into the bone.

In certain instances, the first location may be an articular region of the acetabulum.

In certain instances, the first data points are fit to a sphere.

In certain instances, the first bone may be an ilium, the first location may be an acetabulum, and the second location may be an iliac crest.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a femur and a pelvis.

FIG. 1B is a perspective view of a hip joint formed by the femur and pelvis of FIG. 1A.

FIG. 2A is an exploded perspective view of a femoral component and an acetabular component for a total hip replacement procedure.

FIG. 2B is a perspective view illustrating placement of the femoral component and acetabular component of FIG. 2A in relation to the femur and pelvis of FIG. 1A, respectively.

FIG. 3A is a perspective view of an embodiment of a surgical system.

FIG. 3B is a perspective view of an embodiment of a robotic arm of the surgical system of FIG. 3A.

FIG. 4 illustrates an embodiment of a computer display for use during a surgical procedure.

FIG. 5 illustrates an embodiment of steps of a hip replacement procedure.

FIGS. 6 and 7 illustrate an embodiment of a pelvic registration method shown on a display screen.

FIG. 8A illustrates an embodiment of steps of a pelvic registration method.

FIG. 8B illustrates a table showing various characteristics of many of the steps of the pelvic registration method of FIG. 8A.

FIG. 9A is a lateral view of a three-dimensional bone model of the patient pelvis showing a highlighted band along the articular surface of the acetabulum.

FIG. 9B is a lateral view of the patient pelvis intra-operatively with a distal tip of a navigational probe contacting a point on the articular surface of the acetabulum.

FIG. 9C depicts, on the left, a sphere generated by captured points on the articular surface of the acetabulum, and, on the right, a ¾ segment of the sphere in order to show the radius of the sphere.

FIG. 9D depicts a later view of the three-dimensional bone model with a point of center of rotation determined pre-operatively from medical imaging of the patient pelvis.

FIG. 10A is an antero-lateral view of the three-dimensional bone model with a point highlighted on the anterior acetabular rim.

FIG. 10B is a lateral view of the patient pelvis intra-operatively with a distal tip of a navigational probe contacting a point on the anterior acetabular rim.

FIG. 10C is an antero-lateral view of the three-dimensional bone model with a point highlighted on the posterior articular surface of the acetabulum.

FIG. 10D is a lateral view of the patient pelvis intra-operatively with a distal tip of a navigational probe contacting a point on the posterior articular surface of the acetabulum.

FIG. 10E is a postero-lateral view of the three-dimensional bone model with a point highlighted on the posterior acetabular rim.

FIG. 10F is a lateral view of the patient pelvis intra-operatively with a distal tip of a navigational probe contacting a point on the posterior acetabular rim.

FIG. 10G is a postero-lateral view of the three-dimensional bone model with a point highlighted on the anterior articular surface of the acetabulum.

FIG. 10H is a lateral view of the patient pelvis intra-operatively with a distal tip of a navigational probe contacting a point on the anterior articular surface of the acetabulum.

FIG. 11A is an antero-lateral view of the three-dimensional bone model with a point highlighted on the anterior superior iliac spine.

FIG. 11B is a lateral view of the patient pelvis intra-operatively with a distal tip of a navigational probe contacting a point on the ASIS.

FIG. 11C is a lateral view of the three-dimensional bone model depicting a pair of vectors in order to measure angular orientation relative to an acetabular plane.

FIG. 12A is lateral view of the three-dimensional bone model of the patient pelvis with a highlighted band on the anterior and superior aspect of the acetabular rim.

FIG. 12B is a lateral view of the patient pelvis intra-operatively with a distal tip of a navigational probe contacting a point on the anterior aspect of the acetabular rim.

FIG. 12C is lateral view of the three-dimensional bone model of the patient pelvis with a highlighted band on the posterior and superior aspect of the acetabular rim.

FIG. 12D is a lateral view of the patient pelvis intra-operatively with a distal tip of a navigational probe contacting a point on the posterior aspect of the acetabular rim.

FIG. 13A is an anterior view of the three-dimensional bone model depicting a pair of vectors in order to measure inclination about a plane that is perpendicular to the acetabular plane.

FIG. 13B is a postero-lateral view of the three-dimensional bone model with a point highlighted on the posterior acetabular rim, and a first embodiment of graphic surrounding the point, where the graphic is spaced apart from the point by a first radius.

FIG. 13C is a postero-lateral view of the three-dimensional bone model with a point highlighted on the posterior acetabular rim, and a first embodiment of graphic surrounding the point, where the graphic is spaced apart from the point by a second radius.

FIG. 13D is a postero-lateral view of the three-dimensional bone model with a point highlighted on the posterior acetabular rim, and a second embodiment of graphic surrounding the point, where the graphic is spaced apart from the point by a first radius.

FIG. 13E is a postero-lateral view of the three-dimensional bone model with a point highlighted on the posterior acetabular rim, and a second embodiment of graphic surrounding the point, where the graphic is spaced apart from the point by a second radius.

FIG. 14 is an example computing system having one or more computing units that may implement various systems and methods discussed herein is provided.

FIG. 15A is a posterior view of a knee joint.

FIG. 15B is an anterolateral view of a shoulder joint.

FIG. 15C is an anterolateral view of an elbow joint.

FIG. 15D is a medial view of an ankle joint.

FIG. 16A is a posterior view of the pelvis showing the geometric relationship between the posterior superior iliac spines and a distal sacrum.

FIG. 16B is a posterior view of the spinal column showing the geometric relationship between the distal most joints and the proximal most joints.

FIG. 17A illustrates bone pins, a clamping device, and a navigated probe for use on a patient's iliac crest in a registration procedure.

FIG. 17B illustrates bone pins, a clamping device, and a navigated probe for use on a patient's iliac crest in a registration procedure.

FIG. 17C illustrates a bone pin and a navigated probe for use on a patient's iliac crest in a registration procedure.

FIG. 17D illustrates bone pins, a clamping device, and a navigated probe for use on a patient's iliac crest in a registration procedure.

FIG. 17E illustrates bone pins, a clamping device, a navigated probe, and a sleeved registration tool for use on a patient's iliac crest in a registration procedure.

FIG. 18A is an isometric, exploded front view of a bone pin clamp.

FIG. 18B is an isometric front view of a bone pin clamp.

FIG. 18C is a first side view of the bone pin clamp.

FIG. 18D is a second side view, opposite the first side view, of the bone pin clamp.

FIG. 18E is a top view of the bone pin clamp.

FIG. 18F is a bottom view of the bone pin clamp.

FIG. 18G is a front view of the bone pin clamp.

FIG. 18H is a back view of the bone pin clamp.

FIG. 19A is an isometric front view of a bone pin guide.

FIG. 19B is a first side view of the bone pin guide.

FIG. 19C is a second side view, opposite the first side view, of the bone pin guide.

FIG. 19D is a top view of the bone pin guide.

FIG. 19E is a bottom view of the bone pin guide.

FIG. 19F is a front view of the bone pin guide.

FIG. 19G is a back view of the bone pin guide.

FIG. 20A is an anterolateral view of a pelvis.

FIG. 20B is an anterolateral view of a pelvis with the bone pin guide positioned against the iliac crest of the ilium.

FIG. 20C is an anterolateral view of a pelvis with the bone pin guide positioned against the iliac crest of the ilium, and with a first bone pin positioned through a first guide of the bone pin guide.

FIG. 20D is an anterolateral view of a pelvis with the bone pin guide positioned against the iliac crest of the ilium, and with the second bone pin positioned through a second guide of the bone pin guide.

FIG. 20E is an anterolateral view of a pelvis with the two bone pins positioned in the iliac crest of the ilium, and with the bone pin guide removed.

FIG. 20F is an anterolateral view of a pelvis with the two bone pins positioned in the iliac crest of the ilium, and with the bone pin clamp being positioned over the two bone pins.

FIG. 20G is an anterolateral view of a pelvis with the two bone pins positioned in the iliac crest of the ilium, and with the bone pin clamp positioned over the two bone pins.

FIG. 20H is an anterolateral view of a pelvis with the bone pin clamp positioned over the two bone pins, and with a third bone pin delivered through the third guide of the bone pin guide.

FIG. 20I is a close-up view of the bone pin clamp positioned over the three bone pins.

FIG. 20J is a close-up view of the bone pin clamp positioned over the three bone pins with a tracker array coupled to the clamp via a tracker coupling.

FIG. 20K is a close-up view of the bone pin clamp positioned over the three bone pins with a tracker array coupled to the clamp via a tracker coupling, and with a navigated probe contacting a registration indent of the clamp.

FIG. 21A is a flowchart of a method of registration using the bone pin guide and bone pin clamp.

FIG. 21B is a flowchart of a computer-implemented method of registration using the bone pin clamp.

FIG. 22A is an isometric view of a bone pin guide and a bone pin clamp positioned on an iliac crest.

FIG. 22B is an isometric view of a bone pin guide positioned on an iliac crest.

DETAILED DESCRIPTION

The present application incorporates by reference the following applications in their entireties: U.S. patent application Ser. No. 12/894,071, filed Sep. 29, 2010, entitled “SURGICAL SYSTEM FOR POSITIONING PROSTHETIC COMPONENT AND/OR FOR CONSTRAINING MOVEMENT OF SURGICAL TOOL”; U.S. patent application Ser. No. 13/234,190, filed Sep. 16, 2011, entitled “SYSTEMS AND METHOD FOR MEASURING PARAMETERS IN JOINT REPLACEMENT SURGERY”; U.S. patent application Ser. No. 11/357,197, filed Feb. 21, 2006, entitled “HAPTIC GUIDANCE SYSTEM AND METHOD”; U.S. patent application Ser. No. 12/654,519, filed Dec. 22, 2009, entitled “TRANSMISSION WITH FIRST AND SECOND TRANSMISSION ELEMENTS”; U.S. patent application Ser. No. 12/644,964, filed Dec. 22, 2009, entitled “DEVICE THAT CAN BE ASSEMBLED BY COUPLING”; and U.S. patent application Ser. No. 11/750,807, filed May 18, 2007, entitled “SYSTEM AND METHOD FOR VERIFYING CALIBRATION OF A SURGICAL DEVICE”.

I. Overview

The hip joint is the joint between the femur and the pelvis and primarily functions to support the weight of the body in static (e.g., standing) and dynamic (e.g., walking) postures. FIG. 1A illustrates the bones of an operative side of a hip joint 10, which include a left pelvis or ilium 12 and a proximal end of a left femur 14. While a right pelvis and proximal end of a right femur is not shown in FIG. 1A, such a discussion herein is applicable to both the right and the left femur and pelvis without limitation. Continuing on, the proximal end of the femur 14 includes a femoral head 16 disposed on a femoral neck 18. The femoral neck 18 connects the femoral head 16 to a femoral shaft 20. As shown in FIG. 1B, the femoral head 16 fits into a concave socket in the pelvis 12 called the acetabulum 22, thereby forming the hip joint 10. The acetabulum 22 and femoral head 16 are both covered by articular cartilage that absorbs shock and promotes articulation of the joint 10.

Over time, the hip joint 10 may degenerate (e.g., due to osteoarthritis) resulting in pain and diminished functionality. As a result, a hip replacement procedure, such as total hip arthroplasty or hip resurfacing, may be necessary. During hip replacement, a surgeon replaces portions of a patient's hip joint 10 with artificial components. In total hip arthroplasty, the surgeon removes the femoral head 16 and neck 18 and replaces the native bone with a prosthetic femoral component 26 comprising a head 26 a, a neck 26 b, and a stem 26 c (shown in FIG. 2A). As shown in FIG. 2B, the stem 26 c of the femoral component 26 is anchored in a cavity the surgeon creates in the intramedullary canal of the femur 14. Alternatively, if disease is confined to the surface of the femoral head 16, the surgeon may opt for a less invasive approach in which the femoral head is resurfaced (e.g., using a cylindrical reamer) and then mated with a prosthetic femoral head cup (not shown). Similarly, if the natural acetabulum 22 of the pelvis 12 is worn or diseased, the surgeon resurfaces the acetabulum 22 using a reamer and replaces the natural surface with a prosthetic acetabular component 28 comprising a hemispherical shaped cup 28 a (shown in FIG. 2A) that may include a liner 28 b. To install the acetabular component 28, the surgeon connects the cup 28 a to a distal end of an impactor tool and implants the cup 28 a into the reamed acetabulum 22 by repeatedly striking a proximal end of the impactor tool with a mallet. If the acetabular component 28 includes a liner 28 b, the surgeon snaps the liner 28 b into the cup 28 a after implanting the cup 28 a. Depending on the position in which the surgeon places the patient for surgery, the surgeon may use a straight or offset reamer to ream the acetabulum 22 and a straight or offset impactor to implant the acetabular cup 28 a. For example, a surgeon that uses a postero-lateral approach may prefer straight reaming and impaction whereas a surgeon that uses an antero-lateral approach may prefer offset reaming and impaction.

II. Exemplary Robotic System

A surgical system described herein may be utilized to perform hip replacement, as well as other surgical procedures. As shown in FIG. 3A, an embodiment of a surgical system 5 for surgical applications according to the present disclosure includes a computer assisted navigation system 7, a tracking device 8, a computer 15, a display device 9 (or multiple display devices 9), and a robotic arm 30.

The robotic arm 30 can be used in an interactive manner by a surgeon to perform a surgical procedure on a patient, such as a hip replacement procedure. As shown in FIG. 3B, the robotic arm 30 includes a base 32, an articulated arm 34, a force system (not shown), and a controller (not shown). A surgical tool 58 (e.g., a rotary burring device as seen in FIG. 3A, an end effector 40 having an operating member as seen in FIG. 3B) is coupled to an end of the articulated arm 34, and the surgeon manipulates the surgical tool 58 by grasping and manually moving the articulated arm 34 and/or the surgical tool.

The force system and controller are configured to provide control or guidance to the surgeon during manipulation of the surgical tool. The force system is configured to provide at least some force to the surgical tool via the articulated arm 34, and the controller is programmed to generate control signals for controlling the force system. In one embodiment, the force system includes actuators and a backdriveable transmission that provide haptic (or force) feedback to constrain or inhibit the surgeon from manually moving the surgical tool beyond predefined virtual boundaries defined by haptic objects as described, for example, in U.S. patent application Ser. No. 11/357,197 (Pub. No. US 2006/0142657), filed Feb. 21, 2006, and/or U.S. patent application Ser. No. 12/654,519, filed Dec. 22, 2009, each of which is hereby incorporated by reference herein in its entirety. In a certain embodiment the surgical system is the RIO™. Robotic Arm Interactive Orthopedic System manufactured by MAKO Surgical Corp. of Fort Lauderdale, Fla. The force system and controller are preferably housed within the robotic arm 30.

The tracking device 8 is configured to track the relative locations of the surgical tool 58 (coupled to the robotic arm 30) and the patient's anatomy. The surgical tool 58 can be tracked directly by the tracking device 8. Alternatively, the pose of the surgical tool can be determined by tracking the location of the base 32 of the robotic arm 30 and calculating the pose of the surgical tool 58 based on joint encoder data from joints of the robotic arm 30 and a known geometric relationship between the surgical tool and the robotic arm 30. In particular, the tracking device 8 (e.g., an optical, mechanical, electromagnetic, or other known tracking system) tracks (or enables determination of) the pose (i.e., position and orientation) of the surgical tool and the patient's anatomy so the navigation system 7 knows the relative relationship between the tool and the anatomy.

In operation, a user (e.g., a surgeon) manually moves the robotic arm 30 to manipulate the surgical tool 58 (e.g., the rotary burring device, the end effector 40 having an operating member) to perform a surgical task on the patient, such as bone cutting or implant installation. As the surgeon manipulates the tool 58, the tracking device 8 tracks the location of the surgical tool and the robotic arm 30 provides haptic (or force) feedback to limit the surgeon's ability to move the tool 58 beyond a predefined virtual boundary that is registered (or mapped) to the patient's anatomy, which results in highly accurate and repeatable bone cuts and/or implant placement. The robotic arm 30 operates in a passive manner and provides haptic feedback when the surgeon attempts to move the surgical tool 58 beyond the virtual boundary. The haptic feedback is generated by one or more actuators (e.g., motors) in the robotic arm 30 and transmitted to the surgeon via a flexible transmission, such as a cable drive transmission. When the robotic arm 30 is not providing haptic feedback, the robotic arm 30 is freely moveable by the surgeon and preferably includes a virtual brake that can be activated as desired by the surgeon. During the surgical procedure, the navigation system 7 displays images related to the surgical procedure on one or both of the display devices 9.

To aid in tracking the various pieces of equipment within the system, the robotic arm 30 may include a device marker 48 to track a global or gross position of the robotic arm 30, a tool end marker 54 to track the distal end of the articulating arm 34, and a free-hand navigation probe 56 for use in the registration process. Each of these markers 48, 54, 56 (among others such as navigation markers positioned in the patient's bone) is trackable by the tracking device 8 with optical cameras, for example.

The navigation system 7 described herein may be any type of navigation system 7 known in the art without limitation. For example, the navigation system 7 may be an optical navigation system that optically tracks elements on a tracker array, an electromagnetic navigation system that uses magnetic fields and sensors to detect position, an ultrasound navigation system that scans bone surfaces and tool positions, fiber optic navigation systems utilizing fiber optic cables attached to components of the system, and mechanical arm navigation systems with arm encoders through the linkage.

The computer 15 may include a display and an input device (e.g., keyboard, mouse) and is configured to communicate with the navigation system 7, the tracking device 8, the various display devices 9 in the system, and the robotic arm 30. Furthermore, the computer 15 may receive information related to a particular surgical procedure and perform various functions related to performance of the surgical procedure. For example, the computer 15 may have software as necessary to perform functions related to image analysis, surgical planning, registration, navigation, image guidance, and haptic guidance. A more detailed analysis of an example computing system having one or more computing units that may implement various systems and methods discussed herein, is described subsequently in reference to FIG. 14 .

FIG. 3B depicts an end effector 40 particularly suited for use in robotic assisted hip arthroplasty. The end effector 40 is configured to be mounted to an end of the robotic arm 30. The end effector 40 includes a mounting portion 50, a housing, a coupling device, and a release member. The end effector 40 is configured to individually and interchangeably support and accurately position multiple operating members relative to the robotic arm 30. As seen in FIG. 3B, the end effector 40 is coupled to an operating member 100. The end effector 40 and related tools, systems, and methods are described in U.S. patent application Ser. No. 12/894,071, filed Sep. 29, 2010, which is hereby incorporated by reference in its entirety.

The mounting portion (or mount) 50 preferably couples the end effector 40 to the robotic arm 30. In particular, the mounting portion 50 extends from the housing and is configured to couple the end effector 40 to a corresponding mounting portion 35 of the robotic arm 30 using, for example, mechanical fasteners, such that the mounting portions are fixed relative to one another. The mounting portion 50 can be attached to the housing or formed integrally with the housing and is configured to accurately and repeatably position the end effector 40 relative to the robotic arm 30. In one embodiment, the mounting portion 50 is a semi-kinematic mount as described in U.S. patent application Ser. No. 12/644,964, filed Dec. 22, 2009, and hereby incorporated by reference herein in its entirety.

The end effector 40 in FIG. 3B is one example of a surgical tool that can be tracked and used by the surgical robotic arm 30. Other tools (e.g., drills, burrs) as known in the art can be attached to the robotic arm for a given surgical procedure.

III. Pre-Operative Planning a Surgical Procedure

Prior to the surgical procedure, a preoperative CT (computed tomography) scan of the patient's pelvis 12 and femur 14 is generated with a medical imaging device. While the discussion will focus on CT scans, other imaging modalities (e.g., MRI) may be similarly be employed. Additionally and alternatively, X-ray images derived from the CT scan and/or the three-dimensional models 512, 514 can be used for surgical planning, which may be helpful to surgeons who are accustomed to planning implant placement using actual X-ray images as opposed to CT based models. The CT scan may be performed by the surgeon or at an independent imaging facility. Additionally or alternatively, intra-operative imaging methods may be employed to generate a patient model of the bone. For example, various boney surfaces of interest may be probed with a tracked probe to generate a surface profile of the surface of interest. The surface profile may be used as the patient bone model. Accordingly, the present disclosure is applicable to all methods of generating a patient bone model or a portion thereof.

As shown in FIG. 4 , the CT scan or data from the CT scan is segmented and to obtain a three-dimensional model 512 of the pelvis 12 and a three-dimensional model 514 of the femur 14. The three-dimensional models 512, 514 are used by the surgeon to construct a surgical plan. The surgeon generates a surgical plan by designating a desired pose (i.e., position and orientation) of the acetabular component and the femoral component relative to the models 512, 514 of the patient's anatomy. For example, a planned pose 500 of the acetabular cup can be designated and displayed on a computer display, such as the display device 9. During the surgical procedure, motion of the patient's anatomy and the surgical tool in physical space are tracked by the tracking device 8, and these tracked objects are registered to corresponding models in the navigation system 7 (image space). As a result, objects in physical space are correlated to corresponding models in image space. Therefore, the surgical system 5 knows the actual position of the surgical tool relative to the patient's anatomy and the planned pose 500, and this information is graphically displayed on the display device 9 during the surgical procedure.

In certain embodiments, the models 512, 514 may be of the full bone surfaces 12, 14 respectively. In certain embodiments, the models 512, 514 may be trimmed three-dimensional models providing only critical regions of interest such as the acetabulum 22 and femoral head 16. That is, the trimmed three-dimensional models represent only a portion of the full bone models 512, 514. In certain embodiments, the models 512, 514 may be the combination of multiple models. For example, model 512 may be the combination of individual three-dimensional models of the operative pelvis, non-operative pelvis, and spine.

IV. Intra-Operative Procedures

A.

FIG. 5 illustrates an embodiment of intra-operative steps of performing a total hip replacement. In this embodiment, steps S1-S7, S9, S11, and S12 can be performed with or without robotic assistance. In other embodiments, S1-S2 may not be required, S3-S5 could be done before S1-S2, and S7 could be done at any point before S8. Steps S8 and S10 are preferably performed using the robotic arm 30. For example, step S8 (reaming) can be performed using the robotic arm 30 of FIG. 3 with the end effector 40 coupled to the operating member 100, and step S10 (impacting) can be performed using the robotic arm 30 with the end effector 40 coupled to another operating member.

In step S1 of the surgical procedure, a tracking array is attached to the femur 14 to enable the tracking device 8 to track motion of the femur 14. In step S2, the femur 14 is registered (using any known registration technique) to correlate the pose of the femur 14 (physical space) with the three-dimensional model 514 of the femur 14 in the navigation system 7 (image space). Additionally, the femur checkpoint is attached. In step S3, the femur 14 is prepared to receive a femoral implant (e.g., the femoral component 26) using a navigated femoral broach.

B. Tracking and Registration of Pelvis

1. Overview

In step S4 of FIG. 5 , an acetabular tracking array is attached to the pelvis 12 to enable the tracking device 8 to track motion of the pelvis 12. In step S5, a checkpoint is attached to the pelvis 12 for use during the surgical procedure to verify that the acetabular tracking array has not moved in relation to the pelvis 12. The checkpoint can be, for example, a checkpoint as described in U.S. patent application Ser. No. 11/750,807 (Pub. No. US 2008/0004633), filed May 18, 2007, and hereby incorporated by reference herein in its entirety.

In step S6, the pelvis 12 is registered to correlate the pose of the pelvis 12 (physical space) with the three-dimensional model 512 of the pelvis 12 in the navigation system 7 (image space). In certain embodiments, as shown in FIG. 6 , registration is accomplished using the tracked navigation probe 56 to collect points on the pelvis 12 (physical space) that are then matched to corresponding points on the three-dimensional model 512 of the pelvis 12 (image space). In certain embodiments, registration may be accomplished using a tool that is coupled to the end effector 40 of the robotic arm 30. In certain embodiments, registration may be accomplished with any tool or device that is tracked with the navigation system 7. Two methods of registering the three-dimensional model 512 of the pelvis (image space) and the pelvis 12 (physical space) are described in the subsequent sections of this application.

2. First Pelvic Registration Method

As shown in FIG. 6 , the display device 9 may show the representation 512 of the pelvis 12, including one or more registration points 516. The registration points 516 help the surgeon understand where on the actual anatomy to collect points with the tracked probe. The registration points 516 can be color coded to further aid the surgeon. For example, a registration point 516 on the pelvis 12 to be collected next with the tracked probe can be colored yellow, while registration points 516 that have already been collected can be colored green and registration points 516 that will be subsequently collected can be colored red. After registration, the display device 9 can show the surgeon how well the registration algorithm fit the physically collected points to the representation 512 of the pelvis 12.

For example, as shown in FIG. 7 , error points 518 can be displayed to illustrate how much error exists in the registration between the surface of the representation 512 and the corresponding surface of the physical pelvis 12. In one embodiment, the error points 518 can be color coded, for example, with error points 518 representing minimal error displayed in green and error points 518 representing increasing amounts of error displayed in blue, yellow, and red. As an alternative to color coding, error points 518 representing different degrees of error could have different shapes or sizes. Verification points 519 can also be displayed. The verification points 519 illustrate to the surgeon where to collect points with the tracked probe to verify the registration. When a registration point 519 is collected, the software of the navigation system 7 displays the error (e.g., numerically in millimeters) between the actual point collected on the anatomy and the registered location of the representation 512 in physical space. If the registration error is too high, the surgeon re-registers the pelvis 12 by repeating the registration process of step S6.

This type of registration method requires the surgeon to continually switch his or her focus from the display device 9 showing the representation 512 of the pelvis 12, including one or more registration points 516, to the patient's physical pelvis 12 in order to collect accurate points. Switching focus takes time, and accurately estimating where the registration points 516 are on the patient's physical pelvis 12 takes even more time. In such a registration method described in this section, it may take at least forty-three points to complete an accurate registration.

3. Second Pelvic Registration Method

This section describes another registration method for registering the patient pelvis 12 (physical space) with the three-dimensional model 512 (image space) of the pelvis 12 using a tracked probe 56 or other tool (e.g., end of robotic arm 30). The method described in this section may reduce the total number of collected points as compared with the previously described registration method. For example, with the method described in this section, a surgeon may complete an accurate registration with thirty-two points or less. Additionally, much of the registration described in this section is a region-based point collection, as opposed to a point-based point collection. In a region-based point collection, the surgeon is permitted to collect points within a region of the patient's bone, as opposed to an exact point as identified on the three-dimensional bone model 512. This permits the surgeon to focus on the patient's anatomy, and collect points within the permitted region on the bone without having to switch his or her focus to the display screen 9 and back to the patient's physical pelvis 12. Collecting points within a permitted region increases accuracy as it is easier for the surgeon to collect points within a region encompassing many possible locations of permissible points, as compared with a single permissible point.

The patient pelvis 12 is referred to as in the “physical space” because the surgeon is physically using the tracked probe 56 to contact the patient pelvis 12 intra-operatively where the position and orientation of the probe 56 is known and tracked by the tracking device 8 and the navigation system 7. The three-dimensional model 512 of the pelvis 12 is referred to as in the “image space” because the model 512 is a computerized representation of the pelvis 12, which, in certain implementations, may be taken from pre-operative medical images (e.g., CT, MRI) of the patient pelvis 12. As stated previously, in certain implementations, the model 512 of the pelvis may be generated other ways, such as via intra-operatively tracking the pelvis over the bone surface to generate a bone surface profile, and in some embodiments a generic pelvis model may be presented.

In sum, use of the terms “physical space” and “image space” are utilized herein to clarify when reference is made to the patient's physical pelvis 12 or a three-dimensional bone model 512, which is a representation of the patient pelvis 12 provided as a three-dimensional image, respectively.

Reference is made to FIG. 8A, which shows a flowchart of the pelvic registration method 800. The method 800 may include an initial registration 802 to provide an initial mapping of the patient pelvis 12 (physical space) with the three-dimensional model 512 (image space) with respect to position and orientation. The method 800 may also include a fine registration 816 for fine tuning of the position and orientation.

i. Initial Registration

As seen in FIG. 8A, the initial registration 802 includes a step of capturing the center of rotation 804, capturing acetabular landmarks 808, and capturing a distant reference point 814. Capturing the acetabular landmarks 808 may include a step of capturing points on the acetabular rim 810, and a step of capturing points on the surface of the acetabulum 812.

In discussing each step in the registration method 800, reference will be made to FIG. 8B, which is a chart depicting the steps of the initial and fine registration 802, 816, along with an overview of characteristics associated with each step. The Landmark/Region column indicates the portion of the pelvis that is at issue in each step of the method 800. The Capture Method column indicates whether the method of capturing points or data is a point-based collection method or a region-based collection method. The difference between the two methods will be discussed subsequently. The Used By column indicates whether the particular step of the method 800 may be used in initial or fine registration 802, 816. The Approach Dependent column indicates whether or not the system 5 will vary the procedure based on the particular surgical approach. For example, step 810 indicates that capturing points on the acetabular rim is approach dependent. Thus, the system 5 may indicate points for capturing during initial registration that are specific for the chosen surgical approach (e.g., direct anterior, antero-lateral, postero-lateral). In a direct anterior approach, for instance, the system 5 may identify points for capturing on the anterior acetabular rim since this particular area of the acetabulum is more accessible than others, such as the posterior acetabular rim.

Lastly, the Captured In column indicates where and when the points are captured. Each row indicates “Pre-Op/Intra-Op Registration”. While all steps of the method 800 occur during intra-operative registration on the patient pelvis (physical space), the points captured during the intra-operative registration must be compared with pre-operatively identified landmarks that correspond with the intra-operatively captured points in order to orient or register the patient pelvis 12 (physical space) with the three-dimensional bone model 512 of the patient pelvis 12 (image space). Thus, each of the landmarks in the Landmark/Region column are identified in the three-dimensional bone model 512 which is generated based on pre-operatively images (e.g., CT, MRI) of the patient pelvis 12. These locations of pre-operative landmarks, relative to each other, are compared with the locations of the intra-operatively registered points to determine the accuracy of the registration process.

The discussion will now focus on the steps of the initial registration 802 and, in particular, the step of registering the center of rotation 804. For this, reference is made to FIGS. 9A-9B, which depict, respectively, a lateral view of the three-dimensional model 512 of the pelvis 12 and a lateral view of the pelvis 12 (physical space). As seen in FIG. 9A, the three-dimensional model 512 of the pelvis 12, as viewed on a display screen 9, includes a highlighted band 824 on the articular or lunate surface 826 of the acetabulum 22. The articular surface 826 is crescent-shaped and is typically covered by articular cartilage, which is not shown in the three-dimensional model 512. The non-articular area of the acetabulum 22 is the acetabular fossa 828. The articular surface 826 of the acetabulum 22 is hemispherical in shape and abuts the femoral head (not shown) and allows it to rotate within the acetabulum 22.

To register the center of rotation 804, as seen in FIG. 8 , a surgeon may use the navigational probe 56 to capture, collect, or record data points (referred to as patient data) on the patient pelvis 12 (physical space), as seen in FIG. 9B, at multiple points along the articular surface 826 of the acetabulum 22 that corresponds to the highlighted band 824 on the three-dimensional model 512 of the pelvis 12. An alternative embodiment could use a navigational probe 56 or the tracked femur 14 that allows a surgeon to rotate within the acetabulum 22 thereby establishing a dataset representing the center of rotation 804. Capturing, collecting, or recording data points means that the system 5 (e.g., computer 15) stores the location of the points relative to each other in a common coordinate system. An algorithm is then used to integrate the captured points into the coordinate system of the three-dimensional bone model 512 to register or align the patient pelvis 12 (physical space) with the model 512. In this way and upon completion of registration, a representation of the distal end a surgical tool 58 of the robotic arm 30 of the surgical system 5 may be displayed on the display 9 relative to the three-dimensional bone model 512 in a way that appropriately corresponds with the physical location and orientation of the distal end of the surgical tool 58 with respect to the actual patient pelvis 12 (physical space).

Capturing data points or patient data within the highlighted band 824 may be referred to as a region-based point collection as opposed to a point-based collection because acceptable points may be captured throughout the articular surface 826 corresponding to the highlighted band 824. In a point-based collection system, a specific point may be depicted on the three-dimensional model 512 of the pelvis 12 and the surgeon may be queried to capture a data point at the specific point on the patient pelvis 12 (physical space) that corresponds to the specific point on the three-dimensional model 512.

In a certain embodiment, the system 5 may require the distance between any two points 830 to be spaced apart from each other a certain amount. The system 5 may require the distance between any two points 830 to be greater than 5 mm. The system 5 may require the distance between any two points 830 to be less than 80 mm. The system 5 may have an algorithm that defines a required distance between any two points 830 based on other inputs (e.g. acetabulum 22 or acetabular component 28). The system 5 may vary the distance between any two points 830 during point capture. Such a requirement may facilitate the dispersion of captured points 830 so that all points 830 are not captured in one region of the articular surface 826, for example. In certain embodiments, the system 5 may not require a defined distance spacing between points 830. In certain embodiments, the collected point 830 that is not satisfied the minimum spacing distance requirement may be rejected as an outlier or still be used for the point-to-model surface matching in fine registration 816.

In a certain embodiment, the system 5 may require a maximum and/or a minimum number of points 830 to be collected on the articular surface 826. The system may require at least ten points 830 be captured. Additionally or alternatively, the system 5 may require less than twenty points 830 be captured.

Referring to FIG. 9C, the system 5 can use the captured points 830 on the highlighted band 824 to define a sphere 832 with a center point 840 and a radius 834 since the articular surface 826 of the acetabulum 22 is spherical. Stated differently, the system 5 can generate a sphere 832 using the location of the captured points 830 because their locations relative to each other along with a best-fit calculation of the points 830 can be fitted to a sphere 832. From the size of the sphere 832, the radius 834 (or diameter, volume, etc.) can be determined.

It is noted that the sphere 832 on the left in FIG. 9C illustrates the highlighted band 824 and the points 830 on a spherical surface of the sphere 832. The sphere 832 on the right illustrates a ¾ segment of the sphere 832 in order to depict the radius 834.

In a certain embodiment, the system 5 may optimize the number of points 830 by stopping point 830 collection when points 830 are more than the minimum number of points 830 but less than the maximum number of points 830. The system 5 may use an algorithm such as convergence metrics to determine the stopping criterion/criteria. In a certain embodiment, a convergence metric can be the difference between the radius 834 calculated using N collected points 830 and the radius 834 calculated using a subset of collected points 830, such as N−1 collected points 830. If the difference between the two radii 834 is smaller than a predefined threshold, the system 5 ends the point 830 collection early before the points 830 reach the maximum number of points 830. In a certain embodiment, the convergence metrics can be calculated every time when a new point 830 is collected.

As seen in FIG. 9D, a center of rotation point 836 may be pre-operatively determined based on the three-dimensional bone model 512 of the pelvis 12. A radius 838 may then be determined from the center of rotation point 836 to the articular surface 826 of the acetabulum. The center of rotation point 836 may be determined based on pre-operative scans of the patient pelvis 12 and femoral head 16.

The size of the sphere 832 or, more particular, the radius 834 of the sphere 832 as determined from the intra-operative capturing of the points 830, or patient data (physical space), as in FIG. 9C, may be compared with the radius 838 from the center of rotation point 836 as determined from the three-dimensional bone model 512 (image space), as seen in FIG. 9D. That is, the intra-operatively collected patient data (e.g., sphere 832 and radius 834 in FIG. 9C) may be compared with the pre-operatively determined values (e.g., radius 838 of FIG. 9D) to determine the variation there between.

More particularly, the system 5 may require a certain minimum difference between the two radii 834, 838 before the user of the system 5 may continue beyond step 804 of the initial registration 802. In certain embodiments, the system 5 may require the radii 834, 838 to be less than 5 mm different from each other. In certain embodiments, the system 5 may require the radii 834, 838 to be less than 4 mm different from each other. In certain embodiments, the system 5 may require the radii 834, 838 to be less than 3 mm different from each other. In certain embodiments, the system 5 may require the radii 834, 838 to be less than 2 mm different from each other. In certain embodiments, the system 5 may require the radii 834, 838 to be less than 1 mm different from each other.

If the difference between the radii 834, 838 is within allowable tolerances, the system 5 (e.g., computer 15) may merge the location of the center point 840 of the sphere 832 as determined from the intra-operative capturing of the points 830 with the center of rotation point 836 as determined from the three-dimensional bone model 512. In this way, the translational orientation or aspect of registering the patient pelvis 12 (physical space) with the three-dimensional bone model 512 of the pelvis 12 (image space) into a common coordinate system is fixed or locked into place. Stated differently, three degrees of freedom (i.e., translation in x, y, and z directions) may be fixed or preliminarily determined upon merging the center point 840 of the sphere 832 with the center of rotation point 836; thus, three degrees of freedom (i.e., rotation about the x, y, and z directions) are yet unknown.

In general, the system 5 is able to simplify the anatomy based on the CT scans to a patient specific geometrical feature. And then it generates a similar geometry based on the patient data from the captured points. The CT-based patient specific geometric feature is then compared with the intra-operatively captured geometric feature. The result of the comparison reflects the quality of points capturing and bone registration.

The subsequent steps of the registration process determine the rotational orientation of the patient pelvis 12 (physical space) with respect to the three-dimensional bone model 512 of the pelvis (image space) such the robotic arm 30 of the system 5 will be oriented similarly in the image space and the physical space with respect to the bone model 512 of the pelvis and the patient pelvis, respectively.

Once the center of rotation 804 is calculated or captured, various other points of patient data such as acetabular landmarks may be captured 808, as shown in FIG. 8 . As stated previously, the capturing of the acetabular landmarks 808 may be used to determine the rotational orientation of the pelvis 12 (physical space) with the three-dimensional bone model 512 of the pelvis 12 (image space). And since the translational relationship between the physical space and the image space is known by being fixed at the center of rotation point 836, the various acetabular landmarks captured at step 808 may be used to check the distances between the landmarks and the center of rotation point 836.

Capturing patient data as points on the acetabular landmarks at step 808 are point-based and may be approach dependent. As described previously, point-based data capture means that a point is identified (e.g., highlighted with a dot) on the three-dimensional bone model 512 of the pelvis 12 (image space) and the surgeon is queried to select the corresponding point on the patient pelvis (physical space) with the navigational probe 56. The system 5 (e.g., computer 15) can then compare the distances between, for example, the center of rotation point 836 and the highlighted point on the three-dimensional bone model 512, and the center 840 of the sphere 832 and the intra-operatively captured point.

To begin the discussion of capturing acetabular landmarks at step 808, first is a description of antero-lateral and direct anterior approaches for capturing points on the acetabulum rim and articular surface at steps 810 and 812, at FIGS. 10A-10D. Second, is a description of postero-lateral approaches for capturing points on the acetabulum rim and articular surfaces at steps 810 and 812, illustrated in FIGS. 10E-Though not described, the methods herein may be applied to other hip surgical approaches (e.g. direct superior) or to the capture of landmarks for registering other joints (e.g. shoulder, elbow, knee, ankle), as shown in FIGS. 15A-15D.

Reference is made to FIGS. 10A and 10B, which are, respectively, an antero-lateral view of the three-dimensional bone model 512 of the patient pelvis 12 (image space) and a lateral view of the patient pelvis 12 (physical space). As seen in FIG. 10A, the system 5 may identify (e.g., highlight) one or more points 842 on the anterior aspect of the acetabular rim 844 that forms the outer edge of the acetabulum 22 on the three-dimensional bone model 512 of the patient pelvis (image space). The system 5 may then query the surgeon, as seen in FIG. 10B, to capture the corresponding point(s) 842 on the patient pelvis 12 (physical space) by touching the distal end of the navigational probe 56 against the point 842 and logging, collecting, or capturing the position of the point 842 as patient data within the system 5. As seen in FIG. 10B, the point 842 on the anterior aspect of the acetabular rim 844 is accessible by the surgeon from a direct anterior approach or an antero-lateral approach.

For each point 842 identified by the system 5 and captured by the surgeon, the system 5 may then compare the distance between the identified point 842 and the center of rotation point 836 (image space), as seen in FIGS. 9D and 10A, with the intra-operatively gathered distance between the captured point 842 and the center point 840 of the sphere 832, of FIGS. 9C and 10B.

In certain embodiments, the system 5 may identify and query the surgeon to capture a single point 842 on the anterior aspect of the acetabular rim 844. In certain embodiments, the system 5 may identify and query the surgeon to capture two points 842 on the anterior aspect of the acetabular rim 844. In certain embodiments, the system 5 may identify and query the surgeon to capture five points 842 on the anterior aspect of the acetabular rim 844. In certain embodiments, the system 5 may identify and query the surgeon to capture ten points 842 on the anterior aspect of the acetabular rim 844. In certain embodiments, the system 5 may identify and query the surgeon to capture fifteen points 842 on the anterior aspect of the acetabular rim 844. In certain embodiments, the system 5 may identify and query the surgeon to capture another number of points 842 on the anterior aspect of the acetabular rim 844.

In certain embodiments, the system 5 may display one point 842 at a time on the three-dimensional bone model 512 and require the surgeon to capture the corresponding point 842 on the patient pelvis 12 (physical space) before the system 5 displays another point 842 on the three-dimensional bone model 512. In other embodiments, the system 5 may display all points 842 (e.g., 1, 2, 5, 10, 15) on the three-dimensional bone model 512 of the pelvis and allow the surgeon to capture the corresponding points in any order he or she chooses.

Continuing on with capturing the acetabular landmarks, the surgeon may also capture one or more points on the acetabular articular surface, at step 812 of FIG. 8 . As seen in FIG. 10C, which is an antero-lateral view of the three-dimensional bone model 512 of the patient pelvis 12 (image space), one or more points 846 may be identified (e.g., highlighted) on a posterior aspect of the articular surface 826 of the acetabulum 22 of the three-dimensional bone model 512 of the patient pelvis (image space). The system 5 may query the surgeon, as seen in FIG. 10D, which is a lateral view of the patient pelvis 12 (physical space), to capture the corresponding point(s) 846 on the posterior aspect of the patient pelvis 12 (physical space) by touching the distal end of the navigational probe 56 against the point(s) 846 and logging, collecting, or capturing the position of the point(s) 846 as patient data within the system 5. As seen in FIG. 10D, the point 846 on the posterior aspect of the acetabulum 22 is accessible by the surgeon from a direct anterior approach or an antero-lateral approach.

For each point 846 identified by the system 5 and captured by the surgeon, the system 5 may then compare the distance between the identified point 846 and the center of rotation point 836 (image space), as seen in FIGS. 9D and 10C, with the intra-operatively gathered distance between the captured point 846 and the center point 840 of the sphere 832, of FIGS. 9C and 10D.

In certain embodiments, the system 5 may identify and query the surgeon to capture a single point 846 on the posterior aspect of the acetabulum 22. In certain embodiments, the system 5 may identify and query the surgeon to capture two points 846 on the posterior aspect of the acetabulum 22. In certain embodiments, the system may identify and query the surgeon to capture five points 846 on the posterior aspect of the acetabulum 22. In certain embodiments, the system 5 may identify and query the surgeon to capture ten points 846 on the posterior aspect of the acetabulum 22. In certain embodiments, the system 5 may identify and query the surgeon to capture fifteen points 846 on the posterior aspect of the acetabulum 22. In certain embodiments, the system 5 may identify and query the surgeon to capture another number of points 846 on the posterior aspect of the acetabulum 22.

In certain embodiments, the system 5 may display one point 846 at a time on the three-dimensional bone model 512 and require the surgeon to capture the corresponding point 846 on the patient pelvis 12 (physical space) before the system 5 displays another point 846 on the three-dimensional bone model 512. In other embodiments, the system 5 may display all points 846 (e.g., 1, 2, 5, 10, 15) on the three-dimensional bone model 512 of the pelvis and allow the surgeon to capture the corresponding points in any order he or she chooses.

The following is a discussion of postero-lateral approaches for capturing points on the acetabulum rim and articular surfaces at steps 810 and 812. Reference is made to FIGS. 10E-10F for capturing points on the acetabular rim 844 and to FIGS. for capturing points on the articular surface 826 of the acetabulum 22.

As seen in FIG. 10E, which is a postero-lateral view of the three-dimensional bone model 512 of the pelvis 12 (image space) displayed on a display screen 9, one or more points 848 may be identified (e.g., highlighted) on a posterior aspect of the acetabular rim 844 of the acetabulum 22 of the three-dimensional bone model 512 of the patient pelvis (image space). The system 5 may query the surgeon, as seen in FIG. 10F, which is a lateral view of the patient pelvis 12 (physical space), to capture the corresponding point(s) 848 on the posterior aspect of the acetabular rim 844 of the patient pelvis 12 (physical space) by touching the distal end of the navigational probe 56 against the point(s) 848 and logging, collecting, or capturing the position of the point(s) 848 as patient data within the system 5. As seen in FIG. 10F, the point 848 on the posterior aspect of the acetabulum rim 844 is accessible by the surgeon from a postero-lateral approach.

For each point 848 identified by the system 5 and captured by the surgeon, the system 5 may then compare the distance between the identified point 848 and the center of rotation point 836 (image space), as seen in FIGS. 9D and 10E, with the intra-operatively gathered distance between the captured point 848 and the center point 840 of the sphere 832, of FIGS. 9C and 10F.

In certain embodiments, the system 5 may identify and query the surgeon to capture a single point 848 on a posterior aspect of the acetabular rim 844. In certain embodiments, the system 5 may identify and query the surgeon to capture two points 848 on a posterior aspect of the acetabular rim 844. In certain embodiments, the system 5 may identify and query the surgeon to capture five points 848 on a posterior aspect of the acetabular rim 844. In certain embodiments, the system 5 may identify and query the surgeon to capture ten points 848 on a posterior aspect of the acetabular rim 844. In certain embodiments, the system 5 may identify and query the surgeon to capture fifteen points 848 on a posterior aspect of the acetabular rim 844. In certain embodiments, the system 5 may identify and query the surgeon to capture another number of points 848 on a posterior aspect of the acetabular rim 844.

In certain embodiments, the system 5 may display one point 848 at a time on the three-dimensional bone model 512 and require the surgeon to capture the corresponding point 848 on the patient pelvis 12 (physical space) before the system 5 displays another point 848 on the three-dimensional bone model 512. In other embodiments, the system 5 may display all points 848 (e.g., 1, 2, 5, 10, 15) on the three-dimensional bone model 512 of the pelvis and allow the surgeon to capture the corresponding points in any order he or she chooses.

Now the discussion will focus on capturing anterior acetabular landmarks, at step 812 of FIG. 8 . As seen in FIG. 10G, which is a postero-lateral view of the three-dimensional bone model 512 of the pelvis 12 (image space) displayed on a display screen 9, one or more points 850 may be identified (e.g., highlighted) on an anterior aspect of the articular surface 826 of the acetabulum 22 of the three-dimensional bone model 512 of the patient pelvis 12 (image space). The system 5 may query the surgeon, as seen in FIG. 10H, which is a lateral view of the patient pelvis 12 (physical space), to capture the corresponding point(s) 850 on the anterior aspect of the articular surface 826 of the acetabulum 22 of the patient pelvis 12 (physical space) by touching the distal end of the navigational probe 56 against the point(s) 850 and logging, collecting, or capturing the position of the point(s) 850 as patient data within the system 5. As seen in FIG. 10H, the point 850 on the anterior aspect of the articular surface 826 of the acetabulum 22 is accessible by the surgeon from a postero-lateral approach.

For each point 850 identified by the system 5 and captured by the surgeon, the system 5 may then compare the distance between the identified point 850 and the center of rotation point 836 (image space), as seen in FIGS. 9D and 10G, with the intra-operatively gathered distance between the captured point 850 and the center point 840 of the sphere 832, of FIGS. 9C and 10H.

In certain embodiments, the system 5 may identify and query the surgeon to capture a single point 850 on an anterior aspect of the articular surface 826. In certain embodiments, the system 5 may identify and query the surgeon to capture two points 850 on an anterior aspect of the articular surface 826. In certain embodiments, the system 5 may identify and query the surgeon to capture five points 850 on an anterior aspect of the articular surface 826. In certain embodiments, the system 5 may identify and query the surgeon to capture ten points 850 on an anterior aspect of the articular surface 826. In certain embodiments, the system 5 may identify and query the surgeon to capture fifteen points 850 on an anterior aspect of the articular surface 826. In certain embodiments, the system 5 may identify and query the surgeon to capture another number of points 850 on an anterior aspect of the articular surface 826.

In certain embodiments, the system 5 may display one point 850 at a time on the three-dimensional bone model 512 and require the surgeon to capture the corresponding point 850 on the patient pelvis 12 (physical space) before the system 5 displays another point 850 on the three-dimensional bone model 512. In other embodiments, the system 5 may display all points 850 (e.g., 1, 2, 5, 10, 15) on the three-dimensional bone model 512 of the pelvis and allow the surgeon to capture the corresponding points in any order he or she chooses.

It is noted that the surgeon may select the type of surgical approach within the system 5 so that the steps of capturing acetabular landmarks, at step 808 in FIG. 8 , are only displayed for the selected surgical approach. In this way, for a direct anterior or an antero-lateral surgical approach, as seen in FIGS. 10A-D, the system 5 may only display anterior acetabular rim 844 points 842 and posterior articular surface 826 points 846 on the acetabulum 22. Similarly, for a postero-lateral approach, as seen in FIGS. the system 5 may only display posterior acetabular rim 844 points 848 and anterior articular surface 826 points 850 on the acetabulum 22.

The next step in the initial registration 802, according to FIG. 8 , is to capture a distant reference point 814. For this step 814, reference is made to FIGS. 11A-11C. As seen in FIG. 11A, which is an antero-lateral view of the three-dimensional bone model 512 of the patient pelvis 12 (image space) as displayed on a display screen 9, a point 852 may be identified (e.g., highlighted) on a distant reference point or marker such as the anterior superior iliac spine (“ASIS”) 854. In certain embodiments, the distant reference point may be the iliac spine crest or other landmarks that are spaced apart from the acetabulum 22. In certain embodiments, the distant reference point may be another landmark within the incision. In certain embodiments, the distant reference point may be the ASIS on the non-operative side of the pelvis 12, or another landmark on the non-operative side of the patient.

As seen in FIG. 11B, which is a lateral view of the patient pelvis 12 (physical space), the system 5 may query the surgeon to capture the corresponding point 852 on the ASIS 854 of the patient pelvis 12 (physical space) by touching the distal end of the navigational probe 56 against the point(s) 852 and logging, collecting, or capturing the position of the point(s) 852 as patient data within the system 5. As seen in FIG. 11B, the point 852 on the ASIS 854 of the pelvis 12 is accessible by the surgeon from a multitude of surgical approaches since the ASIS may be identified (e.g., palpated) without an incision into the patient body. In the case of the system 5 using the iliac spine crest, a bone pin incision may be made in order to capture the point 852 on the iliac spine crest. In certain instances, the surgeon may utilize the bone pin guide 1900 and bone pin clamp 1800 as shown in FIGS. 18A-19G, and as described in the flowchart of FIG. 21A. And in certain instances, the surgeon may utilize the tools and methods described and shown in reference to FIGS. 17A-17E.

In certain embodiments, the system 5 may identify and query the surgeon to capture a single point 852 (e.g., ASIS). In certain embodiments, the system 5 may identify and query the surgeon to capture two points 852 (e.g., ASIS, iliac spine crest). In certain embodiments, the system 5 may identify and query the surgeon to capture five points 852. In certain embodiments, the system 5 may identify and query the surgeon to capture ten points 852. In certain embodiments, the system 5 may identify and query the surgeon to capture fifteen points 852. In certain embodiments, the system 5 may identify and query the surgeon to capture another number of points 852.

In certain embodiments, the system 5 may display one point 852 at a time on the three-dimensional bone model 512 and require the surgeon to capture the corresponding point 852 on the patient pelvis 12 (physical space) before the system 5 displays another point 850 on the three-dimensional bone model 512. In other embodiments, the system 5 may display all points 852 (e.g., 1, 2, 5, 10, 15) on the three-dimensional bone model 512 of the pelvis and allow the surgeon to capture the corresponding points in any order he or she chooses.

For each point 852 identified by the system 5 and captured by the surgeon, the system 5 may then compare the distance between the identified point 852 and the center of rotation point 836 (image space), as seen in FIG. 9D AND 11A, with the intra-operatively gathered distance between the captured point 852 and the center point 840 of the sphere 832, of FIGS. 9C and 11B.

As seen in FIG. 11C, which is an antero-lateral view of the three-dimensional bone model 512 of the patient pelvis 12 (image space) as displayed on a display screen 9, an intra-operatively determined vector V1 is compared with a pre-operatively determined vector V2. The intra-operatively determined vector V1 may extend from the center point 840, which is coextensive with the center of rotation point 836, to the intra-operatively captured point 852′, which corresponds to the ASIS 854 of the patient pelvis (physical space). The pre-operatively determined vector V2 may extend from the center of rotation point 836 to the point 852 on the ASIS 854 as determined from the pre-operative image scans (e.g., CT, MRI) of the pelvis 12 (image space).

The vectors V1, V2 may extend from an acetabular plane 856 which is coextensive with the acetabular rim 844. From this plane 856, a normal line centered at the center of rotation 836 may be identified. The angular difference A1 between the vectors V1, V2 may be used to lock the rotational alignment or orientation of the intra-operatively captured points (physical space) with the three-dimensional bone model 512 (image space).

The system 5 may use the corresponding pre-operatively captured landmark points (image space), stored as patient data, as reference and give guidance to the user for capturing the intra-operatively captured landmark points (physical space). In certain embodiments, the system 5 may provide guidance based on the three-dimensional geometry of pre-operatively captured landmark points (image space), and expect the same three-dimensional geometry for the corresponding intra-operatively captured landmark points (physical space). In certain embodiments, the system 5 may use the Euclidean distance of landmark points to provide guidance. In certain embodiments, the system 5 may use the three-dimensional angle between the vectors calculated from the landmark points to provide guidance. In certain embodiments, the system 5 may use the paired-point registration algorithm to best fit the pre-operatively captured landmark points (image space) and the corresponding intra-operatively captured landmark points (physical space), and use a fitting error to provide guidance. The guidance may be visual, audio, or tactile feedback or a combination of each.

Upon the completion of intra-operatively captured landmark points, the system 5 may use an algorithm to calculate the initial registration 802 transform using the intra-operatively captured landmark points (physical space) and the corresponding pre-operatively captured landmark points (image space). In certain embodiments, the system 5 may use a paired-point registration algorithm to compute the initial registration 802 transform. In certain embodiments, the system 5 may use intra-operatively captured landmark points 836, 842, 846, 848, 850, 852 (physical space), stored as patient data, and the corresponding pre-operatively captured landmark points (image space) to compute the initial registration 802 transform. In certain embodiments, the system 5 may only use a subset of the intra-operatively captured landmark points and the corresponding pre-operatively captured landmark points to find the best initial registration 802 transform.

ii. Fine Registration

Referring back to FIG. 8A, fine registration 816 includes a region-based point collection or capture of acetabular landmarks 818. Within this step, points are captured at the acetabular rim 820 and at the articular surface of the acetabulum 822. As seen in FIG. 8B, the region-based capture in the fine registration is approach dependent. FIGS. 12A-12B illustrate an antero-lateral and direct anterior approach to point capture on the acetabular rim 844, and FIGS. 12C-12D illustrate a postero-lateral approach to point capture on the acetabular rim 844. In certain embodiments, registration may be complete without the fine registration 816.

To begin, reference is made to FIGS. 12A and 12B, which are, respectively, a lateral view of the three-dimensional bone model 512 of the patient pelvis 12 (image space) and a lateral view of the patient pelvis 12 (physical space). As seen in FIG. 12A, the system 5 may identify a band 858, which may be highlighted, on the anterior and superior aspect of the acetabular rim 844 that forms the outer edge of the acetabulum 22 on the three-dimensional bone model 512 of the patient pelvis (image space). The band 858 may extend outward a certain amount from the acetabular rim 844. The band 858 may indicate an allowable location for a region-based point collection or capture for a direct anterior or antero-lateral surgical approach.

As seen in FIG. 12B, the system 5 may query the surgeon to capture points 860 on the patient pelvis 12 (physical space), using the navigational probe 56, that correspond with the location of the band 858 on the three-dimensional bone model 512 of the pelvis 12 (image space). Accordingly, the surgeon may contact the distal tip of the navigational probe 56 against various points 860 on the anterior and superior aspect of the acetabular rim 844 and capture, log, collect, or store data associated with the location of each point 860 as patient data within the system 5 (e.g., computer).

For fine registration of the acetabular rim 844 via a postero-lateral approach, as seen in FIG. 12C, which is a lateral view of the three-dimensional bone model 512 of the patient pelvis 12 (image space), the system may identify a band 862, which may be highlighted, on the posterior and superior aspect of the acetabular rim 844 that forms the outer edge of the acetabulum 22 on the three-dimensional bone model 512 of the patient pelvis 12 (image space). The band 862 may indicate an allowable location for a region-based point collection or capture for a postero-lateral surgical approach.

As seen in FIG. 12D, the system 5 may query the surgeon to capture points 864 on the patient pelvis 12 (physical space), using the navigational probe 56, that correspond with the location of the band 862 on the three-dimensional bone model 512 of the pelvis 12 (image space). Accordingly, the surgeon may contact the distal tip of the navigational probe 56 against various points 864 on the posterior and superior aspect of the acetabular rim 844 and capture, log, collect, or store data associated with the location of each point 864 as patient data within the system 5 (e.g., computer).

During the step 820 of collecting points along the acetabular rim 844, the system 5 may require the distance between any two captured points 860 (for anterior and antero-lateral approaches), 864 (for postero-lateral approaches) to be a minimum distance apart from each other. In certain embodiments, the system 5 may require a minimum spacing between two captured points 860, 864 to be at least 1 mm. In certain embodiments, the system 5 may require a minimum spacing between two captured points 860, 864 to be at least 2 mm. In certain embodiments, the system 5 may require a minimum spacing between two captured points 860, 864 to be at least 3 mm. In certain embodiments, the system 5 may require a minimum spacing between two captured points 860, 864 to be at least 4 mm. In certain embodiments, the system 5 may require a minimum spacing between two captured points 860, 864 to be at least 5 mm. In certain embodiments, the system 5 may require a minimum spacing between two captured points 860, 864 to be at least 6 mm. In certain embodiments, the system may require a minimum spacing between two captured points 860, 864 to be at least 7 mm. In certain embodiments, the system 5 may require a different minimum spacing between two captured points 860, 864. In certain embodiments, the system 5 may have an algorithm that defines a required distance between any two points 860, 864 based on other inputs (e.g. acetabulum 22 or acetabular component 28). In certain embodiments, the system 5 may vary the distance between any two points 860, 864 during point capture. Such a requirement may facilitate the dispersion of captured points 860, 864 so that all points 860, 864 are not captured in one region of the acetabular rim 844, for example. In certain embodiments, the system 5 may not require a defined distance spacing between points 860, 864. In certain embodiments, the collected point 860, 864 that is not satisfied the minimum spacing requirement may be rejected as an outlier or still be used for the point-to-model surface matching in fine registration 816.

In certain embodiments, the system 5 may require the surgeon to capture a maximum and/or a minimum number of points 860, 864 for a given surgical approach before proceeding to a subsequent step of the registration process. For example, in certain embodiments the system 5 may require a minimum of twenty points be captured. In certain embodiments the system 5 may require a minimum of fifteen points be captured. In certain embodiments the system 5 may require a minimum of ten points be captured. In certain embodiments the system 5 may require a minimum of five points be captured. In certain embodiments the system 5 may require between ten and twenty points be captured.

In a certain embodiment, the system 5 may optimize the number of points 860, 864 by stopping point 860, 864 collection when points 860, 864 are more than the minimum number of points 860, 864 but less than the maximum number of points 860, 864. The system 5 may use an algorithm such as convergence metrics to determine the stopping criterion/criteria. In a certain embodiment, a convergence metric can be the difference between 1) the root-mean-square error of point-to-model surface matching calculated using N collected acetabular rim points 860, 864 plus the articular surface points 830 and landmark points 842, 846, 848, 850, and 2) the root-mean-square error of point-to-model surface matching calculated using a subset of collected acetabular rim points 860, 864 such as N−1 collected points 860, 864 plus the articular surface points 830 and landmark points 842, 846, 848, 850. If the difference between the two root-mean-square errors is smaller than a predefined threshold, the system 5 ends the point 860, 864 collection early before the points 860, 864 reach the maximum number of points 860, 864. In a certain embodiment, the convergence metrics can be calculated every time when a new point 860, 864 is collected.

Referring back the fine registration 816 of FIG. 8A, the acetabulum articular surface is captured 822 and stored as patient data. This step 822 is similar to the methods described in reference to FIGS. 9A and 9B and, thus, the following discussion will be made with reference to those figures. Also, the discussion in reference to FIGS. 9A and 9B is also applicable to the discussion of step 822. For example, while the minimum distance between the points 830 was discussed in reference to FIGS. 9A and 9B, the system 5 may use the same parameters in the fine registration of the acetabulum articular surface capture 822. For the fine registration at step 822, as seen in FIG. 9A, the system 5 may display on a display screen 9 a highlighted band 824 on the articular surface 826 of the acetabulum 22 on the three-dimensional bone model 512 of the patient pelvis 12 (image space). As discussed previously, this is a region-based point capture where the surgeon may capture points 830 on the patient pelvis 12 (physical space) on any area of the pelvis 12 that corresponds with the highlighted band 824 (i.e., articular surface 826).

As with the methods described in reference to FIGS. 9A-9B, the system 5 may require a certain number of points 830 be captured before moving on to other steps in the registration 800. In certain embodiments, the system 5 may require a minimum of twenty points be captured. In certain embodiments the system 5 may require a minimum of fifteen points be captured. In certain embodiments the system 5 may require a minimum of ten points be captured. In certain embodiments the system 5 may require a minimum of five points be captured. In certain embodiments the system 5 may require between ten and twenty points be captured.

Once all the acetabular rim points 860, 864 are collected, an algorithm may be used to determine the registration transform for fine registration 816. In a certain embodiment, the system 5 may use Iterative Closest Point (ICP) (P. J. Besl, H. D. McKay, A method for registration of 3-D shapes, IEEE Transactions on Pattern Analysis and Machine Intelligence, 1992), a point-to-surface matching algorithm that best fits the intra-operatively captured points (physical space) with the three-dimensional bone model 512 (image space). In certain embodiments, the intra-operatively captured points might be a collection of previously mentioned articular surface points 830, acetabular rim points 860, 864, and landmark points 842, 846, 848, 850. In certain embodiments, the intra-operatively captured points might be a collection of articular surface points 830, acetabular rim points 860, 864, and landmark points 842, 846, 848, 850 with certain points removed (e.g., statistical outliers). In certain embodiments, the intra-operatively captured points might be used for both initial registration 802 and fine registration 816. In certain embodiments, the ICP algorithm may use the initial registration 802 transform as the initial guess to improve fine registration 816.

Using the information from the fine registration 816, quality metrics may be employed to determine the accuracy of registration.

Within the fine registration 816, quality metrics may be employed for checking and verifying the accuracy of the rotational orientation around the acetabular normal, as similarly described with reference to FIG. 11C. As seen in FIG. 11C, an intra-operatively determined vector V1 is compared with a pre-operatively determined vector V2 to determine the difference in rotational orientation between the intra-operatively captured points and the pre-operatively determined points. The intra-operatively determined vector V1 may extend from the center point 840, which is coextensive with the center of rotation point 836, to the intra-operatively captured point 852′, which corresponds to the ASIS 854 of the patient pelvis (physical space). The pre-operatively determined vector V2 may extend from the center of rotation point 836 to the point 852 on the ASIS 854 as determined from the pre-operative image scans (e.g., CT, MRI) of the pelvis 12.

The vectors V1, V2 may extend from an acetabular plane 856, defined in a lateral view, which is coextensive with the acetabular rim 844. From this plane 856, a normal line centered at the center of rotation 836 may be identified. The angular difference A1 between the vectors V1, V2 may be used to lock the rotational alignment or orientation of the intra-operatively captured points (physical space) with the three-dimensional bone model 512 (image space).

Another quality metric, as seen in FIG. 13A, which is an antero-lateral view of the three-dimensional bone model 512 of the patient pelvis 12 (image space) displayed on a display screen 9 of the system 5, may be employed for checking inclination or rotation about a plane 866 perpendicular to the acetabular plane 856 as described in reference to FIG. 11C. As seen in FIG. 13A, vectors V1, V2 are the same vectors as shown and described in reference to FIG. 11C. FIG. 13A simply displays the vectors V1, V2 with respect to a plane 866 that is perpendicular to the acetabular plane 856 so as to measure an angular difference A2 between the vectors V1, V2 in the plane 866. The angle A2 may be used to measure an inclination or angular difference between the three-dimensional bone model 512 of the pelvis 12 (image space) and the patient pelvis 12 (physical space).

Additionally or alternatively, the system 5 may include a quality metric by instructing the user to collect additional points on the patient's anatomy at different locations, and then the system 5 measures the distance between the captured point and the corresponding surface of the three-dimensional bone model 512 to ensure registration accuracy is acceptable. In certain instances, the system 5 may queue the user to collect one verification point. In certain instances, the system 5 may queue the user to collect two verification points. In certain instances, the system 5 may queue the user to collect three verification points. In certain instances, the system 5 may queue the user to collect six verification points. In certain instances, the system 5 may queue the user to collect eight verification points. In certain instances, the system 5 may queue the user to collect up to ten verification points.

The location of the verification points may be locations corresponding to low confidence of registration (e.g., point-to-surface mapping is above a certain threshold). This way, areas of low confidence can be identified and additional points can be captured in these areas to determine if registration can result in a higher confidence in the area. Once the user captures the verification points, the captured points may be added to the original point cloud, and all points may be used in the registration algorithm to refine the registration transform.

In certain instances, the location of the verification points may be approach dependent (e.g., direct anterior) so that the points are within the opening of the incision. In certain instances, the location of the verification points may be spaced apart from previously captured points so as to ensure a minimum distance between each of the captured points, or to ensure a balanced distribution of the captured points.

Upon completion of the fine registration 816, the system 5 may indicate that the registration process 800 is complete, and the surgical procedure may commence.

The following discussion focuses on a graphical user interface (“GUI”) 1000 associated with guiding the capture of landmarks on the patient's anatomy during a registration procedure of a robotic surgery. Such guidance may be useful for the surgeon as he or she may be attempting to locate a physical point on the patient's pelvis 12 while also looking at a corresponding virtual point on the three-dimensional bone model 512 displayed on a display screen 9. In this way, the GUI 1000 may provide guidance to the surgeon that he or she is nearing the physical point on the pelvis 12 that corresponds to the virtual point on the bone model 512.

FIGS. 13B-13C depict a first embodiment of a GUI 1000 that guides a user in capturing a point 1002. FIGS. 13D-13E depict a second embodiment of a GUI 1000 that guides a user in capturing a point 1002.

Referring to FIG. 13B, the GUI 1000 is displayed on a display screen 9, which shows the three-dimensional bone model 512 of the patient pelvis 12 on a portion of the screen 9. A virtual point 1002 is displayed on the bone model 512 for which the user is instructed to capture or collect with the system 5 on the patient's pelvis (physical space) with the navigation probe or other tracked tool (not shown). In certain instances, a radius of the virtual point 1002 (being relative to the patient's anatomy as replicated in the bone model 512) may be about 4 millimeters (mm). In certain instances, the radius of the virtual point 1002 may be other distances such as, for example, 2 mm, 6 mm, or mm, among others.

In the first embodiment, directional arrows or triangles 1004 will appear and surround point 1002 in a generally circular fashion when the tip of the navigation probe or other tracked tool is within a certain radius or distance to the physical point on the patient's pelvis 12 that corresponds with the location of the virtual point 1002 on the bone model 512. In certain instances, the directional arrows 1004 will not be displayed until the tip of the navigation probe is within a 100 mm radius of the physical point that corresponds with the virtual point 1002. In this way, the arrows 1004 may appear and disappear, respectively, as the tip of the navigation probe moves within the 100 mm radius, and moves outside of the 100 mm radius. The radius of 100 mm is exemplary, and may be other distances such as, for example, 50 mm, 150 mm, or 200 mm, among others.

When the tip of the probe approaches and enters a certain radius or distance away from the point on the patient's pelvis 12 corresponding to the point 1002 on the bone model 512 (e.g., 100 mm), the arrows 1004 may appear and be spaced apart from the point 1002 a first radius. As the user moves the tip of the probe closer to the point on the patient's pelvis 12 corresponding to the point 1002 on the bone model 512, the arrows 1004 may move closer to the point 1002, as seen in FIG. 13C. Stated differently, as the user moves the tip of the probe closer to the point on the patient's pelvis 12 corresponding to the point 1002 on the bone model 512, the first radius decreases to a second radius. In certain instances, as the tip of the probe gets progressively closer to the physical point on the patient's pelvis 12 corresponding to the point 1002 on the bone model 512, the arrows 1004 corresponding move progressively closer to the point 1002, and the radius of the arrows 1004 progressively decreases indicating the tip of the probe is near the point 1002 to be captured. In certain instances, the point 1002 and/or the arrows 1004 may change color when the point is captured and/or when the tip of the probe is in a location accurately corresponding to the point 1002.

In this way, the GUI 1000 includes the directional arrows 1004 sequentially transitioning from a first state, as seen in FIG. 13B, where the arrows 1004 are further away from the point 1002, to a second state, as seen in FIG. 13C, where the arrows 1004 are closer to the point 1002. In certain instances, the color of the arrows and/or point 1002 may change when sequentially transitioning from the first state to the second state. For example, the colors may change from red, to yellow, and to green as the tip of the navigation probe progressively moves closer to the point 1002.

Referring to FIGS. 13D, the graphical user interface (“GUI”) 1000 is displayed on a display screen 9, which shows the three-dimensional bone model 512 of the patient pelvis 12 on a portion of the screen 9. A virtual point 1002 is displayed on the bone model 512 for which the user is instructed to capture with the system 5 on the patient's pelvis (physical space) with the navigation probe or other tracked tool (not shown). In certain instances, a radius of the virtual point 1002 (being relative to the patient's anatomy as replicated in the bone model 512) may be about 4 mm. In certain instances, the radius of the virtual point 1002 may be other distances such as, for example, 2 mm, 6 mm, or 10 mm, among others.

In the second embodiment, a reticle 1004 having a circle with partial vertical and horizontal alignment indicators may appear and surround point 1002 when the tip of the navigation probe or other tracked tool is within a certain radius or distance to the physical point on the patient's pelvis 12 that corresponds with the location of the virtual point 1002 on the bone model 512. In certain instances, the reticle 1004 will not be displayed until the tip of the navigation probe is within a 100 mm radius of the physical point that corresponds with the virtual point 1002. In this way, the reticle 1004 may appear and disappear, respectively, as the tip of the navigation probe moves within the 100 mm radius, and moves outside of the 100 mm radius. The radius of 100 mm is exemplary, and may be other distances such as, for example, 50 mm, 150 mm, or 200 mm, among others.

When the tip of the probe approaches and enters a certain radius or distance away from the physical point on the patient's pelvis 12 corresponding to the virtual point 1002 on the bone model 512, the circle of the reticle 1004 may appear and be spaced apart from the point 1002 a first radius. As the user moves the tip of the probe closer to the point on the patient's pelvis 12 corresponding to the point 1002 on the bone model 512, the radius gets smaller such that the circle of the reticle 1004 moves closer to the point 1002, as seen in FIG. 13E. Stated differently, as the user moves the tip of the probe closer to the point on the patient's pelvis 12 corresponding to the point 1002 on the bone model 512, the first radius decreases to a second radius. In certain instances, as the tip of the probe gets progressively closer to the point on the patient's pelvis 12 corresponding to the point 1002 on the bone model 512, the size of the circle (e.g., the radius) of the reticle 1004 corresponding gets progressively smaller and closer to the point 1002 indicating that the tip of the probe is near the point 1002 to be captured. In certain instances, the point 1002 and/or the circle of the reticle 1004 may change color when the point is captured and/or when the tip of the probe is in a location accurately corresponding to the point 1002.

In this way, the GUI 1000 includes a reticle 1004 sequentially transitioning from a first state, as seen in FIG. 13D, where a perimeter of the circle of the reticle 1004 is farther away from the point 1002, to a second state, as seen in FIG. 13E, where the perimeter of the circle of the reticle 1004 is closer to the point 1002. In certain instances, the color of the reticle 1004 and/or point 1002 may change when sequentially transitioning from the first state to the second state. For example, the colors may change from red, to yellow, and to green as the tip of the navigation probe progressively moves closer to the point 1002.

The directional arrows and reticle 1004 may be substituted for other graphics including, but not limited to a bullseye, a pointer, a transparent circle or sphere, or destination pin, among others. Additionally, or alternatively, the graphic may blink, rotate, enlarge, or shrink to indicate a change in distance of the tip of the probe to the point 1002. In certain instances, any graphic may be used that generally identifies the point 1002 on the bone model 512 in a first way when the tip of the probe is a first distance from the point on the patient's pelvis 12 that corresponds with the point 1002, and generally identifies the point 1002 on the bone model 512 in a second way when the tip of the probe is a second distance from the patient's pelvis 12 that corresponds with the point 1002. In this example, the first distance may be further away from the point 1002 than the second distance, and the first way may be the graphic with a first diameter that is larger than a second diameter of the graphic in the second way.

It is noted that the GUI described in reference to FIGS. 13B-E may be utilized at any step in the methods described herein without limitation (e.g., initial registration, fine registration, verification).

While the former sections of this application focus on registration of the pelvis 12, the systems and methods described herein are applicable to intra-operative registration of other bones and joints. FIGS. 15A-15D depict example joints for intra-operative registration including a knee joint 600, a shoulder joint 700, an elbow joint 800, and an ankle joint 900, respectively.

As seen in FIG. 15A, the knee joint 600 includes a distal end of a femur 602 and a proximal end of a tibia 604. The distal end of the femur 602 includes medial and lateral condyles 606. The proximal end of the tibia 604 includes a tibial plateau 608 including medial and lateral portions configured to mate with the corresponding condyles 606 of the femur 602. As the knee joint 600 is articulated, the condyles 606 rotate relative to the tibial plateau 608. A thin layer of cartilage may be positioned between the condyles 606 and the tibial plateau 608. As seen in the figure, the condyles 606 may include a rounded or convex profile, whereas the tibial plateau 608 includes a concave profile. A total knee replacement may replace the distal end of the femur 602 including the condyles 606 with a femoral component of an implant, as well as a tibial component of an implant to replace the tibial plateau 608. During surgical registration of the tibia 604 and femur 602 for the knee arthroplasty, as with the systems and methods described with reference to the pelvis 12, a center of rotation could be calculated for the knee joint 600 based, for example, on a shape of the tibial plateau 608, or otherwise. Similarly, portions of the tibia 604 or femur 602 surrounding the tibial plateau 608 and condyles 606 may be registered, as well as a long point on one or both bones.

As seen in FIG. 15B, the shoulder joint 700 includes a lateral portion of a scapula 702 and a proximal end of a humerus 704. The scapula 702 includes a glenoid cavity 706 which is a shallow pyriform articular surface on a lateral end of the scapula 702. A humeral head 708, which is nearly hemispherical in shape, articulates within the glenoid cavity 706. A conventional total shoulder replacement surgery may replace the humeral head 708 and glenoid cavity 706 with an implant having a stem that fits within the humerus 704 and an implant ball that fits within a glenoid socket component that is fitted to the scapula in place of the glenoid cavity 706. Generally, the humeral head 708 may be considered to include a convex bone portion, while the scapula 702 may be considered to include a concave bone portion. During surgical registration of the scapula 702 and humerus 704 in preparation for a shoulder arthroplasty, as with the systems and methods described with reference to the pelvis 12, a center of rotation could be calculated for the shoulder joint 700 based, for example, on a shape of the glenoid cavity 706, or otherwise. Similarly, portions of the scapula 702 surrounding the glenoid cavity 706 (e.g., a rim of the glenoid cavity 706) may be registered, as well as a long point (e.g., posterior spine of scapula 702, clavicle, acromion).

As seen in FIG. 15C, the elbow joint 800 includes a distal end of a humerus 802, and a proximal end of an ulna 804. The distal end of the humerus 802 includes a trochlea 806 that articulates with a trochlear notch 808 of the ulna 804. The trochlea 806 is convex from anterior to posterior, and concave medial to lateral. The trochlear notch 808 of the ulna 804 is concave anterior to posterior, and convex medial to lateral. The distal end of the humerus 802 also includes a capitulum that articulates with a head of a radius (not shown). Generally, the distal end of the humerus 802 may be considered to include a convex bone portion, while the ulna 804 may be considered to include a concave bone portion. A conventional elbow replacement includes replacing the distal end of the humerus 802 and the proximal end of the ulna 804 with an implant component having a humeral metal stem component, a fixed hinge, and an ulna metal stem component. During surgical registration of the humerus 802 and the ulna 804, as with the systems and methods described with reference to the pelvis 12, a center of rotation could be calculated for the elbow joint 800 based, for example, on a shape of the trochlear notch 808, or otherwise. Similarly, portions of the trochlear notch 808 (e.g., surrounding the notch 808, radial notch) may be registered, as well a long point on the ulna 804.

As seen in FIG. 15D, the ankle joint 900 includes a distal end of the tibia 902 and a talus 904. The fibula is not shown. The distal end of the tibia 902 includes an inferior articular surface or plafond. A superior surface of the talus 904 includes an articular surface or trochlea tali, which is semi-cylindrical, and which mates with the distal end of the tibia 902. Generally, the distal end of the tibia 902 may be considered to include a concave bone portion, while the talus may be considered to include a convex bone portion. In a conventional ankle replacement surgery, the distal end of the tibia 902 and a proximal portion of the talus 904 are replaced with a tibial component and a talar component, respectively. The talar component is typically convex, and mates with the tibial component, which is concave. During surgical registration of an ankle replacement surgery, as with the system and methods described with reference to the pelvis 12, a center of rotation could be calculated for the ankle joint 900 based, for example, on a shape of the distal end of the tibia 902 or plafond, or otherwise. Similarly portions of the distal end of the tibia 902 or plafond (e.g., surrounding area) may be registered, as well as a long point on the tibia 902 (e.g., tibial tuberosity).

FIGS. 16A and 16B depict additional or alternative registration methods for other portions of the body that utilizes pattern geometry to reduce the number of registrations points needed for an accurate registration process. FIG. 16A depicts a posterior view of a pelvis 12 including a left and right ilium 1100, and a sacrum 1102 between the left and right ilium 1100. FIG. 16B depicts a posterior view of a spinal column 1104.

As seen in FIG. 16A, there is a geometric relationship between the right and left posterior superior iliac spine (“PSIS”) 1106 and the distal sacrum 1108. The distal sacrum 1108 may be any point at a medial-lateral midline of the sacrum 110 including, but not limited to, the apex of the sacrum at its connection with the base of the coccyx. The right and left PSIS 1106 and the distal sacrum 1108 define an isosceles triangle with two equal length sides 1110 and two equal angles 1112. Thus, the geometric information can be used in the registration process in a similar manner as the center of rotation calculation described previously. For example, a surgeon may capture the location of the right and left PSIS 1106 and the system 5 may guide the surgeon in capturing the location of the distal sacrum 1108 given that the lengths 1110 to the distal sacrum 1108 from each of the PSIS 1106 must be equal. Knowing the geometric relationship between the boney landmarks may provide guidance to the surgeon by ensuring the location for capturing of the distal sacrum 1108 is taken when the lengths 1110 are equal.

As seen in FIG. 16B, there is a geometric relationship between the most proximal joints 1114 of the spine 1104 and the most distal joints 1116 of the spine 1104. More particularly, the proximal joints 1114 and the distal joints 1116 may define an isosceles trapezoid with parallel bases 1118, 1120 and equal angles 1122 between the distal base 1118 and the legs 1124. Thus, the geometric information can be used in the registration process in a similar manner as the center of rotation calculation described previously to ensure that the surgeon captures accurate points.

V. Pelvic Registration Tools and Methods of Use

The following description of tools, systems, and methods for use in registration procedures reference certain anatomy (e.g., iliac crest) as specific instances of use; however, it is foreseen that the tools, systems, and methods described herein may be used on different anatomical landmarks without limitation. The specific anatomical landmarks, such as the iliac crest, are merely exemplary of a location used in a hip procedure. As such, the tools, systems, and methods described herein may be used on bones associated with surgical procedures on other joints (e.g., knee, ankle elbow, shoulder, spine).

FIGS. 17A-17E depict example tools and methods for use in capturing one or more points on the iliac crest 1700 of the ilium 1702 of the patient. One challenge with locating and capturing a point on the iliac crest 1700 in a hip registration procedure is that such an area may not be easily accessible to the surgeon within the incision opening for the hip procedure. While a separate stab incision may be utilized at the iliac crest 1700 to access and log a data point, it is generally desirable to make as few incisions into the body as possible. The following embodiments involve using a tracker 1704 that is ultimately attached to the patient, for example at the iliac crest 1700, and obtaining the landmark crest point (as illustrated in FIGS. 11A and 11B, and described in the corresponding section of the application, and described in reference to step 814 of FIG. 8A) in or around the incision for the attachment of the tracker 1704. In this example, the iliac crest 1700 is used for tracking purposes in addition to the registration process 1200 defined previously.

FIG. 17A depicts a first embodiment of a device 1706 and method for accessing and capturing one or more data points on the patient's iliac crest 1700. The device 1706 includes three bone pins 1710 and a clamp 1708. The clamp 1706 may include three equally spaced-apart through-bores 1712 for receiving the bone pins 1710 therein in a known orientation relative to each other. The clamp 1706 may include a locking feature (e.g., thumb-screw to compress against the pins 1710) so movement of the pins 1710 relative to the clamp 1706 is restrained once the locking feature is engaged. A tracker 1704 (e.g., optical, electromagnetic, ultrasound, fiber optic, mechanical arm linkage) may be attached or integrated with the clamp. The tracker 1704 may be monitored via a tracking device (e.g., camera) 8 of the navigation system 7. In the first embodiment, a surgeon may access the patient's iliac crest 1700 for landmark acquisition by inserting a probe tip of a tracked probe 56 through one of the pin incisions and contacting the iliac crest 1700 at a point 1714 where the pin 1710 extends into the bone 1702. While the device 1706 depicts three through-bores 1712, the device may include a different number of through-bores 1712 without departing from the teachings of the present disclosure. Additionally or alternatively, the through-bores 1712 are described as being equally-spaced apart, but in certain instances the through-bores 1712 may be un-evenly spaced apart from each other.

FIG. 17B depicts a second embodiment of a device 1706 and method for accessing and capturing one or more data points on the patient's body, for example at the iliac crest 1700. The device 1706 includes three bone pins 1710 and a clamp 1708. The clamp 1708 may include three equally spaced-apart through-bores 1712 for receiving the bone pins 1710 therein in a known orientation relative to each other. The clamp 1708 may include a locking feature (e.g., thumb-screw to compress against the pins 1710) so movement of the pins 1710 relative to the clamp 1708 is restrained once the locking feature is engaged. A tracker 1704 (e.g., optical, electromagnetic, ultrasound, fiber optic, mechanical arm linkage) may be attached or integrated with the clamp 1708. The tracker 1704 may be monitored via a tracking device (e.g., camera) 8 of the navigation system 7. In the second embodiment, a surgeon may access the patient's iliac crest 1700 for landmark acquisition by inserting a probe tip of a tracked probe 56 through a fourth stab incision to contact the iliac crest 1700 at a point 1714 either anterior or posterior side of the pins 1710.

While the device 1706 depicts three through-bores 1712, the device may include a different number of through-bores 1712 without departing from the teachings of the present disclosure. Additionally or alternatively, the through-bores 1712 are described as being equally-spaced apart, but in certain instances the through-bores 1712 may be un-evenly spaced apart from each other.

FIGS. 17C-17E depict a third embodiment of a device 1706 and method for accessing and capturing one or more data points on the patient's body, for example at the iliac crest 1700. The device 1706 includes bone pins 1710, and a clamp 1708. The clamp 1708 may include three equally spaced-apart through-bores 1712 for receiving the bone pins 1710 therein in a known orientation relative to each other. The clamp 1708 may include a locking feature (e.g., thumb-screw to compress against the pins 1710) so movement of the pins 1710 relative to the clamp 1708 is restrained once the locking feature is engaged. A tracker 1704 (e.g., optical, electromagnetic, ultrasound, fiber optic, mechanical arm linkage) may be attached or integrated with the clamp 1708. The tracker 1704 may be monitored via a tracking device (e.g., camera) 8 of the navigation system 7.

While the device 1706 depicts three through-bores 1712, the device may include a different number of through-bores 1712 without departing from the teachings of the present disclosure. Additionally or alternatively, the through-bores 1712 are described as being equally-spaced apart, but in certain instances the through-bores 1712 may be un-evenly spaced apart from each other.

As seen in FIG. 17C, a first bone pin 1710 a may be inserted into the iliac crest 1700 of a patient. Using a tracked probe 56, the surgeon may capture one or more points 1714 approximately where the bone pin 1710 a extends into the bone 1702. The exact point of entry into the bone 1702 cannot be probed since it is occupied by the bone pin 1710 a. The surgeon may additionally capture a point 1716 at the proximal end of the bone pin 1710 a. Then, the system 5 may calculate the length L of the pin calculating the distance between the captured points 1714, 1716.

As seen in FIGS. 17D, the first bone pin 1710 a may be received within a first through-bore 1712 a of the clamp 1708. And two additional bone pins 1710 b, 1710 c may be inserted into the iliac crest 1700 while being guided by the respective second and third through-bores 1712 b, 1712 c of the clamp 1708. The clamp 1708 may be distally advanced relative to the pins 1710 a, 1710 b, 1710 c, and secured in position via the locking feature. A tracker 1704 may be attached to the clamp 1708. The tracked probe 56 may be used to capture a data point 1716 at the proximal end of the first bone pin 1710 a (as in FIG. 17C), and the tracked probe 56 may be used to find the longitudinal axis LA of the first bone pin 1710 a, as seen in FIG. 17D. The tracked probe 56 may, for example, be placed vertically next to the first bone pin 1710 a and the longitudinal axis LAP may be captured. Once the axis LAP is captured, the axis LAP can be moved to intersect the proximal tip of the bone pin 1716 to define the bone pin axis LA. Then, extending the length L of the bone pin 1710 a along the axis LA will yield the exact point 1718 where the bone pin 1710 a extends into the ilium 1702.

The tracked probe 56 can also be used to measure the distance the clamp 1708 is positioned relative to the proximal end of the bone pin 1710 a, as seen in FIG. 17D. This may contribute to orienting the tracker 1704 in its orientation relative to the clamp 1708 and the bone 1702.

FIG. 17E depicts an additional or alternative embodiment to that shown in FIG. 17D. As with FIG. 17D, the first bone pin 1710 a may be received within a first through-bore 1712 a of the clamp 1708. And two additional bone pins 1710 b, 1710 c may be inserted into the iliac crest 1700 while being guided by the respective second and third through-bores 1712 b, 1712 c of the clamp 1708. The clamp 1708 may be distally advanced relative to the pins 1710 a, 1710 b, 1710 c. A tracker 1704 may be attached to the clamp 1708. Next, a sleeve 1720 may be used to measure the proximal end 1716 of the bone pin 1710 a, and the axis LA associated with the bone pin 1710 a to ultimately determine a point 1718 on the iliac crest 1700 in which the bone pin 1710 intersects. The sleeve 1720 includes a distal bore 1722 for receiving the proximal end of the bone pin 1710 a, and a proximal bore 1724 for receiving the distal end of a tracked probe 56. The sleeve 1720 includes a longitudinal axis LAS that is coaxial with the longitudinal axes LAP, LA of the tracked probe 56 and the bone pin 1710 a, respectively, when received in their respective bores 1724, 1722 of the sleeve 1720. In this way, a surgeon may install the sleeve 1720 on the bone pin(s), and insert a tracked probe 56 into the proximal bore 1724 of the sleeve 1720. A data point may be captured with the tracked probe 56 positioned within the sleeve 1720, and the system 5 may determine the point 1718 on the iliac crest 1700 that the bone pin 1710 a intersects, knowing the axis of the bone pin LA and the distance from the bone surface 1718 to the probe tip 1726 (through the bone pin, and sleeve).

While the sleeve 1720 is depicted in FIG. 17E as being used in conjunction with a particular bone pin 1710 a, the sleeve 1720 may be used with any of the bone pins 1710 a, 1710 b, 1710 c without limitation.

FIGS. 18A-18H and 19A-19G depict additional or alternative embodiments of registration tools for computer assisted surgical procedures. FIGS. 20A-20I depict the tools in use on a patient's iliac crest. In general, the tools described hereinafter are designed to guide bone pins into a patient's bone during a registration procedure. And while the procedure described is a hip procedure with the tool used on the iliac crest, the tools are applicable to use on any bone and/or joint associated with a registration procedure. That is, discussion of a hip procedure is merely an exemplary discussion of the tool and one contemplated use. As described herein, the tools guide bone pins into the iliac crest during a hip registration procedure, secure the pins in position relative to the tool, and provide registration points on the tool for capturing with a navigated probe in the registration procedure.

More particular, FIG. 18A depicts an isometric exploded view of a bone pin clamp 1800. As seen in the figure, the bone pin clamp 1800 may include a clamp body 1802 and a barrel, or sleeve 1804 coupled to the clamp body 1802. The clamp body 1802 may form a housing that supports a center lock body 1806, a main lock body 1808, and springs 1816 positioned within the clamp body 1802. The center lock body 1806 and the main lock body 1808 may be adjustably positioned within the clamp body 1802 via engagement with a thumb screw 1810. A back plate 1818 may be coupled to the clamp body 1802 (e.g., welded) so as to enclose the center lock body 1806, main lock body 1808, and springs 1816 within the clamp body 1802.

As seen in FIG. 18A, among others, the clamp body 1802 includes a proximal end 1820 and a distal end 1822. The clamp body 1802 may additionally include three through-holes 1812 a, 1812 b, 1812 c extending in a distal-proximal direction for receiving bone pins there through. The sleeve 1804 extends distally from the distal end 1822 of the clamp body 1802, and terminates at a distal tip 1824, which includes a conical taper in this instance. The central through-hole 1812 b is coaxial with a lumen of the sleeve 1804.

The bone pin clamp 1800 may also include registration indents 1826 on a proximal outer surface 1814 of the clamp body 1802 in known positions for receiving a tip of a navigated probe during the registration process. As seen in FIG. 18A, there are three registration indents 1826; two registration indents 1826 are positioned in corners of the proximal outer surface 1814, and one registration indent 1826 is positioned between two of the through-holes 1812 a, 1812 b. The position and number of the indents 1826 may vary. In certain instances, the bone pin clamp 1800 may include a single registration indent 1826. In certain instances, the bone pin clamp 1800 may include a two registration indent 1826. In certain instances, the bone pin clamp 1800 may include a more than three registration indents 1826.

The proximal outer surface 1814 may also include a window 1828 extending into an inner volume 1830 of the clamp body 1802. The window 1828 may be used to couple the center lock body 1806 with a pair of dowels 1832 during the assembly process. The clamp body 1802 may include a front side 1834, a back side 1836, and a pair of lateral sides 1838, 1840. The back side 1836 includes a rectangular opening 1842 that is enclosed by the back plate 1818, which may be welded to the clamp body 1802 upon completion of the manufacturing of the bone pin clamp 1800.

A front side 1834 of the clamp body 1802 may include a front threaded opening 1844 for receiving the thumb screw 1810 therein. Each of the pair of lateral sides 1838, 1840 includes a side threaded opening 1846, 1848 for receiving a thumb screw.

The bone pin clamp 1800 may additionally include a tracker coupling (not shown) that engages one of the thumb-screws 1810 for securing a tracking member (e.g., optical tracker, electromagnetic tracker, ultrasound tracker, fiber optic tracker, mechanical arm tracker) that is capable of being tracked by the navigation system 7.

As seen in FIG. 18A, the center lock body 1806 may include a pair of through-holes 1850 extending in a distal-proximal direction for receiving the pair of dowels 1832, and a threaded through-hole 1852 extending front a front-back direction for receiving the thumb-screw 1810 therein. The pair of dowels 1832 may extend partially within the window 1828 so the center lock body 1806 is limited in its movement in a front-back direction. When the thumb-screw 1810 is received within the threaded through-hole 1852 of the center lock body 1806, the distal tip of the thumb-screw 1810 may extend beyond the center lock body 1806 and into the opening defined by the center bone pin through-hole 1812 b. When this happens, the thumb-screw 1810 may contact a bone pin positioned within the bone pin through-hole 1812 b so as to secure a position of the bone pin relative to the bone pin clamp 1800.

The main lock body 1808 may include a central recess 1854 for receiving the center lock body 1806 therein. The main lock body 1808 may also include a pair of outer bodies 1856, each including a ledge 1858 on an outer end thereof. Each of the ledges include a partial cylindrical recess for receiving a portion of a thumb-screw (like 1810) extending inward relative to the main lock body 1808. The central recess 1854 may also include a partial cylindrical recess for receiving a portion of a bone pin positioned through the central bone pin through-hole 1812 b. A bone pin positioned in the bone pin through hole 1812 c fits behind the ledge 1858 of the main lock body 1808, and a thumb-screw engaged with the side threaded opening 1846 may contact the bone pin and secure a position of the bone pin relative to the bone pin clamp 1800. Similarly, a bone pin positioned in the bone pin through hole 1812 a fits behind the ledge 1858 of the main lock body 1808, and a thumb-screw engaged with the side threaded opening 1848 may contact the bone pin and secure a position of the bone pin relative to the bone pin clamp 1800.

The bone pin clamp 1800 may include four springs 1816 keeping the main lock body 1808 generally centrally positioned within the inner volume 1830 of the clamp 1800. The springs 1816 may, for example, slightly bias the main lock body 1808 in a position within the inner volume 1830 so the ledges 1858 slightly occupy a space within the through-holes 1812 a, 1812 c. In this way, the clamp 1800 may apply an amount of pressure against the bone pins positioned within the through-holes 1812 a, 1812 c.

The back plate 1818 may include a central through-hole 1860 and a pair of nubs or protrusion 1862 for supporting an end of the springs 1816 and keeping them in a position.

The bone pin clamp 1800 may be part of a registration system that may also include a bone pin guide 1900, as seen in FIGS. 19A-19G. FIG. 19A is an isometric view of the bone pin guide 1900. FIG. 19B is a first side view of the bone pin guide 1900. FIG. 19C is a second side view, opposite the first side view, of the bone pin guide 1900. FIG. 19D is a top view of the bone pin guide 1900. FIG. 19E is a bottom view of the bone pin guide 1900. FIG. 19F is a front view of the bone pin guide 1900. And FIG. 19G is a back view of the bone pin guide 1900.

As seen in FIG. 19A, among others, the bone pin guide 1900 may include a guide body 1902 at a proximal end 1904 and a pair of barrels, tubes, or sleeves 1906 extending distally from the guide body 1902. The guide body 1902 may include a pair of through-holes 1908 spaced apart from each other that lead into an inner volume of the barrels 1906. The guide body 1902 may additionally include a rectangular through-hole 1912 extending transverse to the pair of through-holes 1908 in a front-back direction. The guide body 1902 also may include planar surfaces 1914 on the outer sides 1916 thereof. In certain instances, the planar surfaces 1914 on the outer sides 1916 may be engaged by a tool when using the bone pin guide 1900 to guide bone pins into the bone.

The pair of barrels 1906 are coaxial with the pair of through-holes 1908 of the guide body 1902 and extend distally from a distal surface 1918 of the guide body 1902, and terminate at a distal tip 1920, which may include a conical taper. Opposite the distal surface 1918 is a proximal surface 1922 of the guide body 1902.

The pair of through-holes 1908 of the guide body 1902 of the bone pin guide 1900 are spaced apart from each other the same distance as the outer bone pin through-holes 1812 a, 1812 c. In this way, the bone pin guide 1900 may be used first to guide first and second bone pins into the patient bone (e.g., iliac crest) at predetermined trajectories (e.g., parallel trajectories) and predetermined spacing.

FIGS. 20A-20I illustrate steps in a surgical registration procedure utilizing the bone pin guide 1900 and bone pin clamp 1800 described herein. FIG. 21A is a flowchart showing the steps of the surgical registration procedure 2100.

To begin, reference is made to FIG. 21A. As seen in the flowchart, the method 2100 may include, at step 2102, making an incision (e.g., stab incision) 1924 at the iliac crest 1700. As seen in FIG. 20A, which is an anterolateral view of a patient pelvis, an incision 1924 is made at the iliac crest 1700 of the ilium 1702. Step 2104 of FIG. 21A, as illustrated in FIG. 20B, may include positioning the bone pin guide 1900 up to the iliac crest 1700 such that the distal tips 1920 of the barrels 1906 contact the iliac crest 1700. Step 2106 of FIG. 21A, as illustrated in FIG. 20C, may include inserting or delivering a first bone pin 1710 a though a first through-hole 1908 of the guide body 1902 of the bone pin guide 1900 and into the iliac crest 1700. Delivery of the bone pin may be via a drill or by hand.

Step 2108 of FIG. 21A, as illustrated in FIG. 20D, may include delivering a second bone pin 1710 c though a second through-hole 1908 of the guide body 1902 of the bone pin guide 1900 and into the iliac crest 1700. Step 2110 of FIG. 21A, as illustrated in FIG. 20E, may include removing the bone pin guide 1900 from the pair of bone pins 1710 a, 1710 c such that the bone pins remain positioned in the iliac crest 1700 of the patient. Step 2112 of FIG. 21A, as illustrated in FIGS. 20F and 20G, may include sliding the outer through-holes 1812 a, 1812 c of the bone pin clamp 1800 over the first and second bone pins 1710 a, 1710 c until the distal tip 1824 of the sleeve 1804 contacts the iliac crest 1700. Step 2114 of FIG. 21A, as illustrated in FIG. 20H, may include inserting or delivering a third bone pin 1710 b through the central through-hole 1812 b of the bone pin clamp 1800 and into the iliac crest 1700.

Step 2116 of FIG. 21A, as illustrated in FIG. 20I, may include tightening the three thumb-screws 1810 so as to secure the bone pins 1710 a, 1710 b, 1710 c in relation to the bone pin clamp 1800. Step 2118 of FIG. 21A, as illustrated in FIG. 20J, may include attaching a tracker coupling 1926 to the bone pin clamp 1800, and attaching a tracker array 1704 to the tracker coupling 1926.

Step 2120 of FIG. 21A, as illustrated in FIG. 20K, may include contacting a distal tip of a tracked navigation probe 56 to one or more of the registration indents 1826 on the bone pin clamp 1800 and capturing the position of the probe 56 via the navigation system 7. This step may include calculating a point 1928 the position on the bone 1700 through which the center bone pin 1710 extends through. The point 1928 may be calculated based on the following: the three registration indents 1826 may define a plane that is determined by the surgical system upon being contacted by the navigated probe 56; and, a distance (extending along a longitudinal axis of the sleeve 1804) from the plane (distance being normal to the plane) defined by the three registration indents 1826 to the distal tip 1824 of the sleeve 1804 is known. Therefore, once the plane defined by the three registration indents 1826 is determined, the point 1928 is the distance (from plane to distal tip 1824) normal to the plane. Step 2120 may include using the position on the iliac crest 1700 through which the bone pin 1710 extends into as a reference point in the hip registration algorithm (as the far point). It is noted, that while the longitudinal axis of the sleeve 1804 (the distance described previously) is normal to plane defined by the three registration indents 1826, in certain instances, the sleeve 1804 may be designed to be at an angle other than normal to the plane. In such an instance, the distance (while not being normal to the plane) is still known as it is a known angle relative to the plane. While the bone pin clamp 1800 is described as including three registration indents 1826, the device may include more or fewer indents 1826 without departing from the scope of the present disclosure.

As seen in FIG. 21B, a computer-implemented method 2150 of registration using the bone pin clamp 1800 may include the following. At step 2152, the method 2150 may include receiving first data points 830 in a point-cloud corresponding to points on a patient bone 1702 in a first location that are registered with a navigated instrument. In certain instances, the first location may be an articular region 826 of the acetabulum 22 as described in reference to FIGS. 9A-9B. In certain instances, the first data points 830 are fit to a sphere 832 as described in reference to FIG. 9C. In certain instances, the first bone may be an ilium 1702, the first location may be an acetabulum 22, and the second location may be an iliac crest 1700.

Still referring to FIG. 21B, the method 2150 may include, at step 2154, receiving second data points in the point-cloud corresponding to points on a bone pin clamp 1800 that may be secured to the patient bone 1702 in a second location 1700 via a plurality of bone pins 1710 a, 1710 b, 1710 c, the bone pin clamp 1800 may include a plurality of registration indents 1826 defining a plane, the plane being a known distance from an end of the clamp 1800, which contacts the patient bone 1702. The method 2150, at step 2156, may also include determining a bone surface point 1928 at the second location 1700 from the defined plane and known distance. And, step 2158 of the method 2150 may include registering the first and second data points in the point cloud with image data of the patient bone. In certain instances, the bone surface point may be a point 1928 where one of the plurality of bone pins extends into the bone 1702.

FIGS. 22A and 22B depict additional or alternative registration tools for collecting a far point, for example, on a patient's iliac crest. FIG. 22A depicts an isometric view of a bone pin guide 2200 and a bone pin clamp 2202 secured to bone pins 1710 that extend into the iliac crest 1700 of the ilium 1702. FIG. 22B depicts an isometric view of an alternative bone pin guide 2200 a capable of use with the bone pin clamp 2202 shown in FIG. 22A.

The bone pin guide 2200 of FIG. 22A includes a platform 2204, registration indents 2206 defined on corner projections of the platform 2204, first, second, and third guide through-holes extending through the platform 2204 in a distal-proximal direction, a central sleeve 2208 extending distally from the second (middle) guide through-hole, and outer sleeves (shorter than the central sleeve 2208) 2210 extending distally from the first and third guide through-holes. The registration indents 2206 may define a plane, that once identified, can be used in conjunction with the distance from the plane to the distal tip of the central sleeve 2208 to determine a point at which a bone pin positioned within the second guide through-hole extends into the bone.

The bone pin guide 2200 a of FIG. 22B includes a platform 2204, first, second, and third guide through-holes extending through the platform 2204 in a distal-proximal direction, a central sleeve 2208 extending distally from the second (middle) guide through-hole, and outer sleeves (shorter than the central sleeve 2208) 2210 extending distally from the first and third guide through-holes. The bone pin guide 2200 a also includes a registration barrel 2212 extending proximally from a back side of the guide 2200 a. The barrel 2212 includes a partial through-hole 2214 that does not daylight into an opening on a distal end thereof. The barrel 2212 includes an axis 2216 extending longitudinally through the barrel that intersects an axis extending through the second guide through-hole. In this way, a navigated probe 56 positioned within the barrel 2212 will be aligned with the axis of a bone pin positioned within the second guide-through hole such that the point of intersection of the bone and the second bone pin can be determined and used in the registration process.

The bone pin clamp 2202 of FIG. 22A includes many features of the bone pin clamp 1800 shown in FIGS. 18A-18H except for a distally extending sleeve 1804. The bone pin clamp 2202 may be slid on the platform 2204 of the bone pin guide 2200, 2200 a, and secured in position relative to the guide 2200, 2200 a via the thumb screw 1810. A tracker coupling 2218 may be coupled with the bone pin clamp 2202, 2202 a and a tracker array (not shown in FIGS. 22A-22B) may be coupled to the tracker coupling 2218.

The aforementioned steps of the methods may be performed by a computer or computing system. Additionally or alternatively, the aforementioned steps of the methods may be in the form of instructions for performing a computer process on a computing system, where the instructions are stored in one or more tangible computer-readable storage media.

While various designs are shown and described for the bone pin clamp and bone pin guides, features from the various designs may be combined without limitation.

C. Registering of Robotic Arm

Referring back to FIG. 5 , after registering the pelvis at step S6, the robotic arm 30 may be registered at step S7. In this step, the robotic arm 30 is registered to correlate the pose of the robotic arm 30 (physical space) with the navigation system 7 (image space). The robotic arm 30 can be registered, for example, as described in U.S. patent application Ser. No. 11/357,197 (Pub. No. US 2006/0142657), filed Feb. 21, 2006, and hereby incorporated by reference herein in its entirety.

D. Preparation of the Acetabulum and Performance of the Surgical Procedure

In operation, the surgeon can use the robotic arm 30 of FIG. 3B to facilitate a joint replacement procedure, such as reaming bone and implanting an acetabular cup for a total hip replacement or hip resurfacing procedure. As explained above, the robotic arm 30 includes a surgical tool configured to be coupled to a cutting element (for reaming) and to engage a prosthetic component (for impacting). For example, as seen in FIG. 3B, for reaming, the end effector 40 can couple to the operating member 100, which couples to a cutting element. Similarly, for impacting, the end effector 40 can couple to another operating member, which engages the prosthetic component. The robotic arm 30 can be used to ensure proper positioning during reaming and impacting.

In step S8 of FIG. 5 , the surgeon resurfaces the acetabulum 22 using a reamer, such as the operating member 100, coupled to the robotic arm 30 of FIG. 3B. As described above in connection with the operating member 100, the surgeon couples the appropriate operating member (e.g., a straight or offset reamer) to the end effector connects the cutting element to the received operating member, and manually manipulates the robotic arm 30 to ream the acetabulum 22. During reaming, the robotic arm 30 provides haptic (force feedback) guidance to the surgeon. The haptic guidance constrains the surgeon's ability to manually move the surgical tool to ensure that the actual bone cuts correspond in shape and location to planned bone cuts (i.e., cuts consistent with the surgical plan).

In step S9 of FIG. 5 , the surgeon verifies that the registration (i.e., the geometric relationship) between the acetabular tracking array and the pelvis 12 is still valid by contacting the pelvis checkpoint with a tracked probe as described, for example, in U.S. patent application Ser. No. 11/750,807 (Pub. No. US 2008/0004633), filed May 18, 2007, and hereby incorporated by reference herein in its entirety. If registration has degraded (e.g., because the acetabular tracking array was bumped during reaming), the pelvis 12 is re-registered. Registration verification can be performed any time the surgeon wants to check the integrity of the acetabular registration.

In step S10 of FIG. 5 , the prosthetic component 316 is implanted on the reamed acetabulum 22 using an impactor tool. In a manner identical to that described above in connection with step S8 (reaming), during the impaction step S10, the display device 9 can show the planned pose 500, the activation region 510, the representations 512, 514 of the anatomy, and a representation of the surgical tool, as seen in FIG. 4 . Also as described above in connection with step S8, if the surgeon moves the end effector 40 to override the haptic feedback, the controller can initiate automatic control of the surgical tool to substantially align at least one aspect of the actual pose with the corresponding desired aspect of the target pose.

In step S11 of FIG. 5 , the surgeon installs the femoral component on the femur 14, and in step S12, the surgeon determines leg length and femoral offset. At any time during the surgical procedure, the display device 9 can show data related to progress and/or outcome. For example, after reaming in step S8 and/or impacting in step S10), data relating to the actual position of the reamed acetabulum 22 (or the implanted acetabular cup) can include, for example, numerical data representing error between the actual and planned locations in the three orthogonal planes of the patient's anatomy (i.e., medial/lateral, superior/inferior, and anterior/posterior).

V. Example Computing System

Referring to FIG. 14 , a detailed description of an example computing system 1300 having one or more computing units that may implement various systems and methods discussed herein is provided. The computing system 1300 may be applicable to any of the computers or systems utilized in the preoperative or intra-operative planning of the arthroplasty procedure (e.g., registration), and other computing or network devices. It will be appreciated that specific implementations of these devices may be of differing possible specific computing architectures not all of which are specifically discussed herein but will be understood by those of ordinary skill in the art.

The computer system 1300 may be a computing system that is capable of executing a computer program product to execute a computer process. Data and program files may be input to the computer system 1300, which reads the files and executes the programs therein. Some of the elements of the computer system 1300 are shown in FIG. 14 , including one or more hardware processors 1302, one or more data storage devices 1304, one or more memory devices 1308, and/or one or more ports 1308-1310. Additionally, other elements that will be recognized by those skilled in the art may be included in the computing system 1300 but are not explicitly depicted in FIG. 14 or discussed further herein. Various elements of the computer system 1300 may communicate with one another by way of one or more communication buses, point-to-point communication paths, or other communication means not explicitly depicted in FIG. 14 .

The processor 1302 may include, for example, a central processing unit (CPU), a microprocessor, a microcontroller, a digital signal processor (DSP), and/or one or more internal levels of cache. There may be one or more processors 1302, such that the processor 1302 comprises a single central-processing unit, or a plurality of processing units capable of executing instructions and performing operations in parallel with each other, commonly referred to as a parallel processing environment.

The computer system 1300 may be a conventional computer, a distributed computer, or any other type of computer, such as one or more external computers made available via a cloud computing architecture. The presently described technology is optionally implemented in software stored on the data stored device(s) 1304, stored on the memory device(s) 1306, and/or communicated via one or more of the ports 1308-1310, thereby transforming the computer system 1300 in FIG. 14 to a special purpose machine for implementing the operations described herein. Examples of the computer system 1300 include personal computers, terminals, workstations, mobile phones, tablets, laptops, personal computers, multimedia consoles, gaming consoles, set top boxes, and the like.

The one or more data storage devices 1304 may include any non-volatile data storage device capable of storing data generated or employed within the computing system 1300, such as computer executable instructions for performing a computer process, which may include instructions of both application programs and an operating system (OS) that manages the various components of the computing system 1300. The data storage devices 1304 may include, without limitation, magnetic disk drives, optical disk drives, solid state drives (SSDs), flash drives, and the like. The data storage devices 1304 may include removable data storage media, non-removable data storage media, and/or external storage devices made available via a wired or wireless network architecture with such computer program products, including one or more database management products, web server products, application server products, and/or other additional software components. Examples of removable data storage media include Compact Disc Read-Only Memory (CD-ROM), Digital Versatile Disc Read-Only Memory (DVD-ROM), magneto-optical disks, flash drives, and the like. Examples of non-removable data storage media include internal magnetic hard disks, SSDs, and the like. The one or more memory devices 1306 may include volatile memory (e.g., dynamic random access memory (DRAM), static random access memory (SRAM), etc.) and/or non-volatile memory (e.g., read-only memory (ROM), flash memory, etc.).

Computer program products containing mechanisms to effectuate the systems and methods in accordance with the presently described technology may reside in the data storage devices 1304 and/or the memory devices 1306, which may be referred to as machine-readable media. It will be appreciated that machine-readable media may include any tangible non-transitory medium that is capable of storing or encoding instructions to perform any one or more of the operations of the present disclosure for execution by a machine or that is capable of storing or encoding data structures and/or modules utilized by or associated with such instructions. Machine-readable media may include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more executable instructions or data structures.

In some implementations, the computer system 1300 includes one or more ports, such as an input/output (I/O) port 1308 and a communication port 1310, for communicating with other computing, network, navigation, or robotic devices. It will be appreciated that the ports 1308-1310 may be combined or separate and that more or fewer ports may be included in the computer system 1300.

The I/O port 1308 may be connected to an I/O device, or other device, by which information is input to or output from the computing system 1300. Such I/O devices may include, without limitation, one or more input devices, or output devices, such as, for example, robotic arms, and navigation and tracking systems.

In one implementation, the input devices convert a human-generated signal, such as, human voice, physical movement, physical touch or pressure, and/or the like, into electrical signals as input data into the computing system 1300 via the I/O port 1308. Similarly, the output devices may convert electrical signals received from computing system 1300 via the I/O port 1308 into signals that may be sensed as output by a human, such as sound, light, and/or touch. The input device may be an alphanumeric input device, including alphanumeric and other keys for communicating information and/or command selections to the processor 1302 via the I/O port 1308. The input device may be another type of user input device including, but not limited to: direction and selection control devices, such as a mouse, a trackball, cursor direction keys, a joystick, and/or a wheel; one or more sensors, such as a camera, a microphone, a positional sensor, an orientation sensor, a gravitational sensor, an inertial sensor, and/or an accelerometer; and/or a touch-sensitive display screen (“touchscreen”), and/or tracking/probe devices associated with the navigation and tracking systems. The output devices may include, without limitation, a display, a touchscreen, a speaker, a tactile and/or haptic output device, and/or the like. In some implementations, the input device and the output device may be the same device, for example, in the case of a touchscreen.

In one implementation, a communication port 1310 is connected to a network by way of which the computer system 1300 may receive network data useful in executing the methods and systems set out herein as well as transmitting information and network configuration changes determined thereby. Stated differently, the communication port 1310 connects the computer system 1300 to one or more communication interface devices configured to transmit and/or receive information between the computing system 1300 and other devices by way of one or more wired or wireless communication networks or connections. Examples of such networks or connections include, without limitation, Universal Serial Bus (USB), Ethernet, Wi-Fi, Bluetooth®, Near Field Communication (NFC), Long-Term Evolution (LTE), and so on. One or more such communication interface devices may be utilized via the communication port 1310 to communicate one or more other machines, either directly over a point-to-point communication path, over a wide area network (WAN) (e.g., the Internet), over a local area network (LAN), over a cellular (e.g., third generation (3G) or fourth generation (4G)) network, or over another communication means. Further, the communication port 1310 may communicate with an antenna or other link for electromagnetic signal transmission and/or reception.

In an example implementation, patient data, bone models (e.g., generic, patient specific), transformation software, tracking and navigation software, registration software, and other software and other modules and services may be embodied by instructions stored on the data storage devices 1304 and/or the memory devices 1306 and executed by the processor 1302. The computer system 1300 may be integrated with or otherwise form part of the surgical system 100. The system may be configured for registering patient data gathered intra-operatively from a first bone with a computer model of the first bone in a common coordinate system. The first bone may joint a second bone to form a joint such as, for example, a hip joint, a knee joint, a shoulder joint, an elbow joint, or ankle joint, among others. The system may include a surgical navigation system including a tracking device and a tool (e.g., navigation probe, end of a surgical robotic arm) to be tracked in its movement by the tracking device. Additionally, the system may include a computing device (one or more) in communication with the navigation system. The computing device may perform the following steps: 1) receive first data points of the patient data from first intra-operatively collected points on an articular surface of the concave portion of the bone. The first data points may be collected using the at least one tool. The first data points may correspond in location to a first articular region on the computer model. 2) receive a second data point from a second intra-operatively collected point on the first bone. The second data point may be collected using the at least one tool. The second data point may correspond in location to a second virtual data point on the computer model. 3) determine an intra-operative center of rotation from the first data points. The intra-operative center of rotation may correspond to a physical center of rotation of the second bone relative to the first bone. 4) compare a first distance between the virtual center of rotation and the second virtual data point and a second distance between the intra-operative center of rotation and the second data point. And, 5) run a transformation with the patient data and the computer model so as to have them correspond with respect to position and orientation.

Another implementation carried out on an exemplary computing device may include the following steps: receiving first data points in a point-cloud corresponding to points on a patient bone in a first location that are registered with a navigated instrument; receiving second data points in the point-cloud corresponding to points on a bone pin clamp that may be secured to the patient bone in a second location via a plurality of bone pins, the bone pin clamp may include a plurality of registration indents defining a plane, the plane being a known distance from the patient bone; determining a bone surface point at the second location from the defined plane and known distance; and, registering the first and second data points in the point cloud with image data of the patient bone. In certain instances, the bone surface point may be a point where one of the plurality of bone pins extends into the bone. In certain instances, the first location may be an articular region of the acetabulum as described in reference to FIGS. 9A-9B. In certain instances, the first data points are fit to a sphere as described in reference to FIG. 9C. In certain instances, the first bone may be an ilium, the first location may be an acetabulum, and the second location may be an iliac crest.

The system set forth in FIG. 14 is but one possible example of a computer system that may employ or be configured in accordance with aspects of the present disclosure. It will be appreciated that other non-transitory tangible computer-readable storage media storing computer-executable instructions for implementing the presently disclosed technology on a computing system may be utilized.

In the present disclosure, the methods disclosed herein, for example, those shown in FIGS. 5 and 8A-8B, among others, may be implemented as sets of instructions or software readable by a device. Further, it is understood that the specific order or hierarchy of steps in the methods disclosed are instances of example approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the method can be rearranged while remaining within the disclosed subject matter. The accompanying method claims present elements of the various steps in a sample order, and are not necessarily meant to be limited to the specific order or hierarchy presented.

The described disclosure including any of the methods described herein may be provided as a computer program product, software, or computerized method that may include a non-transitory machine-readable medium having stored thereon instructions, which may be used to program a computer system (or other electronic devices) to perform a process according to the present disclosure. A machine-readable medium includes any mechanism for storing information in a form (e.g., software, processing application) readable by a machine (e.g., a computer). The machine-readable medium may include, but is not limited to, magnetic storage medium, optical storage medium; magneto-optical storage medium, read only memory (ROM); random access memory (RAM); erasable programmable memory (e.g., EPROM and EEPROM); flash memory; or other types of medium suitable for storing electronic instructions.

While the present disclosure has been described with reference to various implementations, it will be understood that these implementations are illustrative and that the scope of the present disclosure is not limited to them. Many variations, modifications, additions, and improvements are possible. More generally, embodiments in accordance with the present disclosure have been described in the context of particular implementations. Functionality may be separated or combined in blocks differently in various embodiments of the disclosure or described with different terminology. These and other variations, modifications, additions, and improvements may fall within the scope of the disclosure as defined in the claims that follow. For example, while the description discusses methods involving the hip, the disclosure is similarly applicable to other joints including the shoulder, ankle, and spine, among others.

In general, while the embodiments described herein have been described with reference to particular embodiments, modifications can be made thereto without departing from the spirit and scope of the disclosure. Note also that the term “including” as used herein is intended to be inclusive, i.e. “including but not limited to.”

The construction and arrangement of the systems and methods as shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.). For example, the position of elements may be reversed or otherwise varied and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present disclosure. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present disclosure. 

1.-20. (canceled)
 21. A registration system for use in a medical procedure on a bone of a patient, the registration system comprising: a bone pin clamp assembly comprising: a body including a guide configured to receive a bone pin there through, the bone pin defining an entry point at which the bone pin extends into the bone of the patient when the bone pin is in the bone; a barrel extending from the body to a distal tip, the barrel having a lumen extending along a longitudinal axis from the body to the distal tip, the lumen aligned with the guide such that the lumen is configured to receive the bone pin there through, the distal tip configured to contact the bone of the patient such that the distal tip is located approximately at the entry point; and a registration marker defined on the body, wherein the longitudinal axis of the lumen is normal to a defined plane extending through the registration marker, a known distance defined between the defined plane and the distal tip of the barrel such that, when the lumen receives the bone pin and the distal tip of the barrel contacts the bone, a location of the entry point is defined along the longitudinal axis at the known distance from the defined plane.
 22. The registration system of claim 21, wherein the registration marker is configured to receive a tip of a registration probe during registration to register a position of the registration marker.
 23. The registration system of claim 21, wherein the registration marker comprises an indent on the body.
 24. The registration system of claim 21, further comprising a registration probe configured to register a position of the registration marker.
 25. The registration system of claim 21, further comprising an adjustable fastener configured to engage the bone pin, wherein the adjustable fastener inhibits movement of the body relative to the bone pin when the adjustable fastener is engaged.
 26. The registration system of claim 25, wherein the body further comprises a threaded through-hole extending into the body and extending into the guide, wherein the adjustable fastener comprises a threaded fastener configured to be received within the threaded through-hole so as to extend into the threaded through-hole.
 27. The registration system of claim 21, wherein the body further comprises a tracker coupling configured to secure a tracker array thereto, the tracker array configured to be monitored by a tracking device of a navigation system.
 28. The registration system of claim 21, wherein a tracker array is integrated into the body, the tracker array configured to be monitored by a tracking device of a navigation system.
 29. The registration system of claim 21, further comprising a navigation system, a tracking device and at least one computer, the tracking device configured to be tracked by the navigation system, the at least one computer in communication with the navigation system and configured to receive positional data associated a position of the registration marker by way of the tracking device being tracked by the navigation system.
 30. The registration system of claim 29, wherein the at least one computer is configured to register the positional data with a computer bone model representative of a patient bone.
 31. The registration system of claim 21, wherein the guide is a through-hole extending through the body, the through-hole being coaxial with the lumen of the barrel.
 32. The registration system of claim 21, further comprising the bone pin.
 33. The registration system of claim 21, wherein the registration marker is a first registration marker, the body further comprising a second registration marker and a third registration marker, the first, second, and third registration markers each configured to receive a tip of a navigated probe during registration, the first, second, and third registration markers defining the defined plane.
 34. The registration system of claim 21, wherein the guide is a first through-hole, the body further comprising a second through-hole and a third through-hole, the second through-hole configured to receive a second bone pin there through, the third through-hole configured to receive a third bone pin there through.
 35. A method of surgical registration comprising: receiving a bone pin into a lumen of a barrel that defines a longitudinal axis, the barrel extending from a body to a distal tip, the bone pin extending from a bone of a patient such that the bone pin defines an entry point at which the bone pin extends into the bone; contacting the distal tip of the barrel to the bone such that the distal tip is located approximately at the entry point; contacting a registration marker defined on the body with a registration probe in a registration procedure, the longitudinal axis being normal to a defined plane extending through the registration marker, a known distance defined between the defined plane and the distal tip of the barrel; and determining a location of the entry point from the defined plane and the known distance.
 36. The method of claim 35, wherein the entry point is located along the longitudinal axis.
 37. The method of claim 35, further comprising engaging an adjustable fastener to the bone pin such that the adjustable fastener inhibits movement of the body relative to the bone pin.
 38. The method of claim 35, wherein the bone is an ilium and the distal tip of the barrel contacts an iliac crest.
 39. The method of claim 35, further comprising tracking a tracker array with a tracking device of a navigation system, the tracker array coupled to the body.
 40. The method of claim 35, further comprising contacting one or more points on the bone of the patient with the registration probe. 